10987 lines
575 KiB
HTML
10987 lines
575 KiB
HTML
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<title>C/C++ Interface For SQLite Version 3</title>
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Small. Fast. Reliable.<br>Choose any three.
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<h1 align="center">
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C-language Interface Specification for SQLite
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</h1>
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<p>This page is intended to be a precise and detailed specification.
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For a tutorial introductions, see instead:
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<ul>
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<li><a href="quickstart.html">SQLite In 3 Minutes Or Less</a> and/or
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<li>the <a href="cintro.html">Introduction To The SQLite C/C++ Interface</a>.
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</ul>
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This same content is also available split out into
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<a href="c3ref/intro.html">lots of small pages</a>.</p>
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<hr>
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<h2>Experimental And Deprecated Interfaces</h2>
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<p>SQLite interfaces can be subdivided into three categories:</p>
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<ol>
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<li>Stable</li>
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<li>Experimental</li>
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<li>Deprecated</li>
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</ol>
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<p>Stable interfaces will be maintained indefinitely in a backwards
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compatible way. An application that uses only stable interfaces
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should always be able to relink against a newer version of SQLite
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without any changes.</p>
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<p>Experimental interfaces are subject to change.
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Applications that use experimental interfaces
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may need to be modified when upgrading to a newer SQLite release, though
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this is rare.
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When new interfaces are added to SQLite, they generally begin
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as experimental interfaces. After an interface has been in use for
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a while and the developers are confident that the design of the interface
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is sound and worthy of long-term support, the interface is marked
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as stable.</p>
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<p>Deprecated interfaces have been superceded by better methods of
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accomplishing the same thing and should be avoided in new applications.
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Deprecated interfaces continue to be supported for the sake of
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backwards compatibility. At some point in the future, it is possible
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that deprecated interfaces may be removed.</p>
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<p>Key points:</p>
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<ul>
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<li>Experimental interfaces are subject to change and/or removal
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at any time.</li>
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<li>Deprecated interfaces should not be used in new code and might
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be removed in some future release.</li>
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</ul>
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<hr>
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<h2>List Of Objects:</h2>
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<div class='columns' style='columns: 14em auto;'>
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<ul style='padding-top:0;'>
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<li><a href='#sqlite3'>sqlite3</a></li>
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<li><a href='#sqlite3_api_routines'>sqlite3_api_routines</a></li>
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<li><a href='#sqlite3_backup'>sqlite3_backup</a></li>
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<li><a href='#sqlite3_blob'>sqlite3_blob</a></li>
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<li><a href='#sqlite3_context'>sqlite3_context</a></li>
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<li><a href='#sqlite3_data_directory'>sqlite3_data_directory</a></li>
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<li><a href='#sqlite3_file'>sqlite3_file</a></li>
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<li><a href='#sqlite3_index_info'>sqlite3_index_info</a></li>
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<li><a href='#sqlite3_int64'>sqlite3_int64</a></li>
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<li><a href='#sqlite3_int64'>sqlite3_uint64</a></li>
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<li><a href='#sqlite3_int64'>sqlite_int64</a></li>
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<li><a href='#sqlite3_int64'>sqlite_uint64</a></li>
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<li><a href='#sqlite3_io_methods'>sqlite3_io_methods</a></li>
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<li><a href='#sqlite3_mem_methods'>sqlite3_mem_methods</a></li>
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<li><a href='#sqlite3_module'>sqlite3_module</a></li>
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<li><a href='#sqlite3_mutex'>sqlite3_mutex</a></li>
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<li><a href='#sqlite3_mutex_methods'>sqlite3_mutex_methods</a></li>
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<li><a href='#sqlite3_pcache'>sqlite3_pcache</a></li>
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<li><a href='#sqlite3_pcache_methods2'>sqlite3_pcache_methods2</a></li>
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<li><a href='#sqlite3_pcache_page'>sqlite3_pcache_page</a></li>
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<li><a href='#sqlite3_stmt'>sqlite3_stmt</a></li>
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<li><a href='#sqlite3_str'>sqlite3_str</a></li>
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<li><a href='#sqlite3_temp_directory'>sqlite3_temp_directory</a></li>
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<li><a href='#sqlite3_value'>sqlite3_value</a></li>
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<li><a href='#sqlite3_vfs'>sqlite3_vfs</a></li>
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<li><a href='#sqlite3_vtab'>sqlite3_vtab</a></li>
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<li><a href='#sqlite3_vtab_cursor'>sqlite3_vtab_cursor</a></li>
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</ul>
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</div>
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<hr>
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<h2>List Of Constants:</h2>
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<p>Also available: <a href="rescode.html">list of error codes</a></p>
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<div class='columns' style='columns: 20em auto;'>
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<ul style='padding-top:0;'>
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<li><a href='#SQLITE_ABORT'>SQLITE_ABORT</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_ABORT_ROLLBACK</a></li>
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<li><a href='#SQLITE_ACCESS_EXISTS'>SQLITE_ACCESS_EXISTS</a></li>
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<li><a href='#SQLITE_ACCESS_EXISTS'>SQLITE_ACCESS_READ</a></li>
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<li><a href='#SQLITE_ACCESS_EXISTS'>SQLITE_ACCESS_READWRITE</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_ALTER_TABLE</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_ANALYZE</a></li>
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<li><a href='#SQLITE_ANY'>SQLITE_ANY</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_ATTACH</a></li>
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<li><a href='#SQLITE_ABORT'>SQLITE_AUTH</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_AUTH_USER</a></li>
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<li><a href='#SQLITE_BLOB'>SQLITE_BLOB</a></li>
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<li><a href='#SQLITE_ABORT'>SQLITE_BUSY</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_BUSY_RECOVERY</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_BUSY_SNAPSHOT</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_BUSY_TIMEOUT</a></li>
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<li><a href='#SQLITE_ABORT'>SQLITE_CANTOPEN</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_CONVPATH</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_DIRTYWAL</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_FULLPATH</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_ISDIR</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_NOTEMPDIR</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CANTOPEN_SYMLINK</a></li>
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<li><a href='#SQLITE_CHECKPOINT_FULL'>SQLITE_CHECKPOINT_FULL</a></li>
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<li><a href='#SQLITE_CHECKPOINT_FULL'>SQLITE_CHECKPOINT_PASSIVE</a></li>
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<li><a href='#SQLITE_CHECKPOINT_FULL'>SQLITE_CHECKPOINT_RESTART</a></li>
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<li><a href='#SQLITE_CHECKPOINT_FULL'>SQLITE_CHECKPOINT_TRUNCATE</a></li>
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<li><a href='#sqliteconfigcoveringindexscan'>SQLITE_CONFIG_COVERING_INDEX_SCAN</a></li>
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|
<li><a href='#sqliteconfiggetmalloc'>SQLITE_CONFIG_GETMALLOC</a></li>
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<li><a href='#sqliteconfiggetmutex'>SQLITE_CONFIG_GETMUTEX</a></li>
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<li><a href='#sqliteconfiggetpcache'>SQLITE_CONFIG_GETPCACHE</a></li>
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<li><a href='#sqliteconfiggetpcache2'>SQLITE_CONFIG_GETPCACHE2</a></li>
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<li><a href='#sqliteconfigheap'>SQLITE_CONFIG_HEAP</a></li>
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<li><a href='#sqliteconfiglog'>SQLITE_CONFIG_LOG</a></li>
|
|
<li><a href='#sqliteconfiglookaside'>SQLITE_CONFIG_LOOKASIDE</a></li>
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|
<li><a href='#sqliteconfigmalloc'>SQLITE_CONFIG_MALLOC</a></li>
|
|
<li><a href='#sqliteconfigmemdbmaxsize'>SQLITE_CONFIG_MEMDB_MAXSIZE</a></li>
|
|
<li><a href='#sqliteconfigmemstatus'>SQLITE_CONFIG_MEMSTATUS</a></li>
|
|
<li><a href='#sqliteconfigmmapsize'>SQLITE_CONFIG_MMAP_SIZE</a></li>
|
|
<li><a href='#sqliteconfigmultithread'>SQLITE_CONFIG_MULTITHREAD</a></li>
|
|
<li><a href='#sqliteconfigmutex'>SQLITE_CONFIG_MUTEX</a></li>
|
|
<li><a href='#sqliteconfigpagecache'>SQLITE_CONFIG_PAGECACHE</a></li>
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<li><a href='#sqliteconfigpcache'>SQLITE_CONFIG_PCACHE</a></li>
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<li><a href='#sqliteconfigpcache2'>SQLITE_CONFIG_PCACHE2</a></li>
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<li><a href='#sqliteconfigpcachehdrsz'>SQLITE_CONFIG_PCACHE_HDRSZ</a></li>
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<li><a href='#sqliteconfigpmasz'>SQLITE_CONFIG_PMASZ</a></li>
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<li><a href='#sqliteconfigscratch'>SQLITE_CONFIG_SCRATCH</a></li>
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<li><a href='#sqliteconfigserialized'>SQLITE_CONFIG_SERIALIZED</a></li>
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<li><a href='#sqliteconfigsinglethread'>SQLITE_CONFIG_SINGLETHREAD</a></li>
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<li><a href='#sqliteconfigsmallmalloc'>SQLITE_CONFIG_SMALL_MALLOC</a></li>
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<li><a href='#sqliteconfigsorterrefsize'>SQLITE_CONFIG_SORTERREF_SIZE</a></li>
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<li><a href='#sqliteconfigsqllog'>SQLITE_CONFIG_SQLLOG</a></li>
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<li><a href='#sqliteconfigstmtjrnlspill'>SQLITE_CONFIG_STMTJRNL_SPILL</a></li>
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<li><a href='#sqliteconfiguri'>SQLITE_CONFIG_URI</a></li>
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<li><a href='#sqliteconfigwin32heapsize'>SQLITE_CONFIG_WIN32_HEAPSIZE</a></li>
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<li><a href='#SQLITE_ABORT'>SQLITE_CONSTRAINT</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_CHECK</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_COMMITHOOK</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_FOREIGNKEY</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_FUNCTION</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_NOTNULL</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_PINNED</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_PRIMARYKEY</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_ROWID</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_TRIGGER</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_UNIQUE</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CONSTRAINT_VTAB</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_COPY</a></li>
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<li><a href='#SQLITE_ABORT'>SQLITE_CORRUPT</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CORRUPT_INDEX</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CORRUPT_SEQUENCE</a></li>
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<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_CORRUPT_VTAB</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_INDEX</a></li>
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|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TABLE</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TEMP_INDEX</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TEMP_TABLE</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TEMP_TRIGGER</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TEMP_VIEW</a></li>
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<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_TRIGGER</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_VIEW</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_CREATE_VTABLE</a></li>
|
|
<li><a href='#sqlitedbconfigdefensive'>SQLITE_DBCONFIG_DEFENSIVE</a></li>
|
|
<li><a href='#sqlitedbconfigdqsddl'>SQLITE_DBCONFIG_DQS_DDL</a></li>
|
|
<li><a href='#sqlitedbconfigdqsdml'>SQLITE_DBCONFIG_DQS_DML</a></li>
|
|
<li><a href='#sqlitedbconfigenablefkey'>SQLITE_DBCONFIG_ENABLE_FKEY</a></li>
|
|
<li><a href='#sqlitedbconfigenablefts3tokenizer'>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</a></li>
|
|
<li><a href='#sqlitedbconfigenableloadextension'>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a></li>
|
|
<li><a href='#sqlitedbconfigenableqpsg'>SQLITE_DBCONFIG_ENABLE_QPSG</a></li>
|
|
<li><a href='#sqlitedbconfigenabletrigger'>SQLITE_DBCONFIG_ENABLE_TRIGGER</a></li>
|
|
<li><a href='#sqlitedbconfigenableview'>SQLITE_DBCONFIG_ENABLE_VIEW</a></li>
|
|
<li><a href='#sqlitedbconfiglegacyaltertable'>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</a></li>
|
|
<li><a href='#sqlitedbconfiglegacyfileformat'>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</a></li>
|
|
<li><a href='#sqlitedbconfiglookaside'>SQLITE_DBCONFIG_LOOKASIDE</a></li>
|
|
<li><a href='#sqlitedbconfigmaindbname'>SQLITE_DBCONFIG_MAINDBNAME</a></li>
|
|
<li><a href='#SQLITE_DBCONFIG_DEFENSIVE'>SQLITE_DBCONFIG_MAX</a></li>
|
|
<li><a href='#sqlitedbconfignockptonclose'>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</a></li>
|
|
<li><a href='#sqlitedbconfigresetdatabase'>SQLITE_DBCONFIG_RESET_DATABASE</a></li>
|
|
<li><a href='#sqlitedbconfigtriggereqp'>SQLITE_DBCONFIG_TRIGGER_EQP</a></li>
|
|
<li><a href='#sqlitedbconfigtrustedschema'>SQLITE_DBCONFIG_TRUSTED_SCHEMA</a></li>
|
|
<li><a href='#sqlitedbconfigwritableschema'>SQLITE_DBCONFIG_WRITABLE_SCHEMA</a></li>
|
|
<li><a href='#sqlitedbstatuscachehit'>SQLITE_DBSTATUS_CACHE_HIT</a></li>
|
|
<li><a href='#sqlitedbstatuscachemiss'>SQLITE_DBSTATUS_CACHE_MISS</a></li>
|
|
<li><a href='#sqlitedbstatuscachespill'>SQLITE_DBSTATUS_CACHE_SPILL</a></li>
|
|
<li><a href='#sqlitedbstatuscacheused'>SQLITE_DBSTATUS_CACHE_USED</a></li>
|
|
<li><a href='#sqlitedbstatuscacheusedshared'>SQLITE_DBSTATUS_CACHE_USED_SHARED</a></li>
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|
<li><a href='#sqlitedbstatuscachewrite'>SQLITE_DBSTATUS_CACHE_WRITE</a></li>
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|
<li><a href='#sqlitedbstatusdeferredfks'>SQLITE_DBSTATUS_DEFERRED_FKS</a></li>
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|
<li><a href='#sqlitedbstatuslookasidehit'>SQLITE_DBSTATUS_LOOKASIDE_HIT</a></li>
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|
<li><a href='#sqlitedbstatuslookasidemissfull'>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</a></li>
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<li><a href='#sqlitedbstatuslookasidemisssize'>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</a></li>
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|
<li><a href='#sqlitedbstatuslookasideused'>SQLITE_DBSTATUS_LOOKASIDE_USED</a></li>
|
|
<li><a href='#SQLITE_DBSTATUS options'>SQLITE_DBSTATUS_MAX</a></li>
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<li><a href='#sqlitedbstatusschemaused'>SQLITE_DBSTATUS_SCHEMA_USED</a></li>
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|
<li><a href='#sqlitedbstatusstmtused'>SQLITE_DBSTATUS_STMT_USED</a></li>
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|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DELETE</a></li>
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|
<li><a href='#SQLITE_DENY'>SQLITE_DENY</a></li>
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|
<li><a href='#SQLITE_DESERIALIZE_FREEONCLOSE'>SQLITE_DESERIALIZE_FREEONCLOSE</a></li>
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|
<li><a href='#SQLITE_DESERIALIZE_FREEONCLOSE'>SQLITE_DESERIALIZE_READONLY</a></li>
|
|
<li><a href='#SQLITE_DESERIALIZE_FREEONCLOSE'>SQLITE_DESERIALIZE_RESIZEABLE</a></li>
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|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DETACH</a></li>
|
|
<li><a href='#sqlitedeterministic'>SQLITE_DETERMINISTIC</a></li>
|
|
<li><a href='#sqlitedirectonly'>SQLITE_DIRECTONLY</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_DONE</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_INDEX</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TABLE</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TEMP_INDEX</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TEMP_TABLE</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TEMP_TRIGGER</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TEMP_VIEW</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_TRIGGER</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_VIEW</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_DROP_VTABLE</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_EMPTY</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_ERROR</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_ERROR_MISSING_COLLSEQ</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_ERROR_RETRY</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_ERROR_SNAPSHOT</a></li>
|
|
<li><a href='#SQLITE_FAIL'>SQLITE_FAIL</a></li>
|
|
<li><a href='#sqlitefcntlbeginatomicwrite'>SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a></li>
|
|
<li><a href='#sqlitefcntlbusyhandler'>SQLITE_FCNTL_BUSYHANDLER</a></li>
|
|
<li><a href='#sqlitefcntlchunksize'>SQLITE_FCNTL_CHUNK_SIZE</a></li>
|
|
<li><a href='#sqlitefcntlckptdone'>SQLITE_FCNTL_CKPT_DONE</a></li>
|
|
<li><a href='#sqlitefcntlckptstart'>SQLITE_FCNTL_CKPT_START</a></li>
|
|
<li><a href='#sqlitefcntlcommitatomicwrite'>SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a></li>
|
|
<li><a href='#sqlitefcntlcommitphasetwo'>SQLITE_FCNTL_COMMIT_PHASETWO</a></li>
|
|
<li><a href='#sqlitefcntldataversion'>SQLITE_FCNTL_DATA_VERSION</a></li>
|
|
<li><a href='#sqlitefcntlfilepointer'>SQLITE_FCNTL_FILE_POINTER</a></li>
|
|
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_GET_LOCKPROXYFILE</a></li>
|
|
<li><a href='#sqlitefcntlhasmoved'>SQLITE_FCNTL_HAS_MOVED</a></li>
|
|
<li><a href='#sqlitefcntljournalpointer'>SQLITE_FCNTL_JOURNAL_POINTER</a></li>
|
|
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_LAST_ERRNO</a></li>
|
|
<li><a href='#sqlitefcntllockstate'>SQLITE_FCNTL_LOCKSTATE</a></li>
|
|
<li><a href='#sqlitefcntllocktimeout'>SQLITE_FCNTL_LOCK_TIMEOUT</a></li>
|
|
<li><a href='#sqlitefcntlmmapsize'>SQLITE_FCNTL_MMAP_SIZE</a></li>
|
|
<li><a href='#sqlitefcntloverwrite'>SQLITE_FCNTL_OVERWRITE</a></li>
|
|
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_PDB</a></li>
|
|
<li><a href='#sqlitefcntlpersistwal'>SQLITE_FCNTL_PERSIST_WAL</a></li>
|
|
<li><a href='#sqlitefcntlpowersafeoverwrite'>SQLITE_FCNTL_POWERSAFE_OVERWRITE</a></li>
|
|
<li><a href='#sqlitefcntlpragma'>SQLITE_FCNTL_PRAGMA</a></li>
|
|
<li><a href='#sqlitefcntlrbu'>SQLITE_FCNTL_RBU</a></li>
|
|
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_RESERVE_BYTES</a></li>
|
|
<li><a href='#sqlitefcntlrollbackatomicwrite'>SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE</a></li>
|
|
<li><a href='#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE'>SQLITE_FCNTL_SET_LOCKPROXYFILE</a></li>
|
|
<li><a href='#sqlitefcntlsizehint'>SQLITE_FCNTL_SIZE_HINT</a></li>
|
|
<li><a href='#sqlitefcntlsizelimit'>SQLITE_FCNTL_SIZE_LIMIT</a></li>
|
|
<li><a href='#sqlitefcntlsync'>SQLITE_FCNTL_SYNC</a></li>
|
|
<li><a href='#sqlitefcntlsyncomitted'>SQLITE_FCNTL_SYNC_OMITTED</a></li>
|
|
<li><a href='#sqlitefcntltempfilename'>SQLITE_FCNTL_TEMPFILENAME</a></li>
|
|
<li><a href='#sqlitefcntltrace'>SQLITE_FCNTL_TRACE</a></li>
|
|
<li><a href='#sqlitefcntlvfsname'>SQLITE_FCNTL_VFSNAME</a></li>
|
|
<li><a href='#sqlitefcntlvfspointer'>SQLITE_FCNTL_VFS_POINTER</a></li>
|
|
<li><a href='#sqlitefcntlwalblock'>SQLITE_FCNTL_WAL_BLOCK</a></li>
|
|
<li><a href='#sqlitefcntlwin32avretry'>SQLITE_FCNTL_WIN32_AV_RETRY</a></li>
|
|
<li><a href='#sqlitefcntlwin32gethandle'>SQLITE_FCNTL_WIN32_GET_HANDLE</a></li>
|
|
<li><a href='#sqlitefcntlwin32sethandle'>SQLITE_FCNTL_WIN32_SET_HANDLE</a></li>
|
|
<li><a href='#sqlitefcntlzipvfs'>SQLITE_FCNTL_ZIPVFS</a></li>
|
|
<li><a href='#SQLITE_BLOB'>SQLITE_FLOAT</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_FORMAT</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_FULL</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_FUNCTION</a></li>
|
|
<li><a href='#SQLITE_DENY'>SQLITE_IGNORE</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_EQ</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_FUNCTION</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_GE</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_GLOB</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_GT</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_IS</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_ISNOT</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_ISNOTNULL</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_ISNULL</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_LE</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_LIKE</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_LT</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_MATCH</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_NE</a></li>
|
|
<li><a href='#SQLITE_INDEX_CONSTRAINT_EQ'>SQLITE_INDEX_CONSTRAINT_REGEXP</a></li>
|
|
<li><a href='#SQLITE_INDEX_SCAN_UNIQUE'>SQLITE_INDEX_SCAN_UNIQUE</a></li>
|
|
<li><a href='#sqliteinnocuous'>SQLITE_INNOCUOUS</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_INSERT</a></li>
|
|
<li><a href='#SQLITE_BLOB'>SQLITE_INTEGER</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_INTERNAL</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_INTERRUPT</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC16K</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC1K</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC2K</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC32K</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC4K</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC512</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC64K</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_ATOMIC8K</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_BATCH_ATOMIC</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_IMMUTABLE</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_POWERSAFE_OVERWRITE</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_SAFE_APPEND</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_SEQUENTIAL</a></li>
|
|
<li><a href='#SQLITE_IOCAP_ATOMIC'>SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_IOERR</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_ACCESS</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_AUTH</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_BEGIN_ATOMIC</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_BLOCKED</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_CHECKRESERVEDLOCK</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_CLOSE</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_COMMIT_ATOMIC</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_CONVPATH</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DATA</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DELETE</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DELETE_NOENT</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DIR_CLOSE</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_DIR_FSYNC</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_FSTAT</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_FSYNC</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_GETTEMPPATH</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_LOCK</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_MMAP</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_NOMEM</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_RDLOCK</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_READ</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_ROLLBACK_ATOMIC</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SEEK</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHMLOCK</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHMMAP</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHMOPEN</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHMSIZE</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_SHORT_READ</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_TRUNCATE</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_UNLOCK</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_VNODE</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_IOERR_WRITE</a></li>
|
|
<li><a href='#sqlitelimitattached'>SQLITE_LIMIT_ATTACHED</a></li>
|
|
<li><a href='#sqlitelimitcolumn'>SQLITE_LIMIT_COLUMN</a></li>
|
|
<li><a href='#sqlitelimitcompoundselect'>SQLITE_LIMIT_COMPOUND_SELECT</a></li>
|
|
<li><a href='#sqlitelimitexprdepth'>SQLITE_LIMIT_EXPR_DEPTH</a></li>
|
|
<li><a href='#sqlitelimitfunctionarg'>SQLITE_LIMIT_FUNCTION_ARG</a></li>
|
|
<li><a href='#sqlitelimitlength'>SQLITE_LIMIT_LENGTH</a></li>
|
|
<li><a href='#sqlitelimitlikepatternlength'>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</a></li>
|
|
<li><a href='#sqlitelimitsqllength'>SQLITE_LIMIT_SQL_LENGTH</a></li>
|
|
<li><a href='#sqlitelimittriggerdepth'>SQLITE_LIMIT_TRIGGER_DEPTH</a></li>
|
|
<li><a href='#sqlitelimitvariablenumber'>SQLITE_LIMIT_VARIABLE_NUMBER</a></li>
|
|
<li><a href='#sqlitelimitvdbeop'>SQLITE_LIMIT_VDBE_OP</a></li>
|
|
<li><a href='#sqlitelimitworkerthreads'>SQLITE_LIMIT_WORKER_THREADS</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_LOCKED</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_LOCKED_SHAREDCACHE</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_LOCKED_VTAB</a></li>
|
|
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_EXCLUSIVE</a></li>
|
|
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_NONE</a></li>
|
|
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_PENDING</a></li>
|
|
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_RESERVED</a></li>
|
|
<li><a href='#SQLITE_LOCK_EXCLUSIVE'>SQLITE_LOCK_SHARED</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_MISMATCH</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_MISUSE</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_FAST</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_RECURSIVE</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_APP1</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_APP2</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_APP3</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_LRU</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_LRU2</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_MAIN</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_MEM</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_MEM2</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_OPEN</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_PMEM</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_PRNG</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_VFS1</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_VFS2</a></li>
|
|
<li><a href='#SQLITE_MUTEX_FAST'>SQLITE_MUTEX_STATIC_VFS3</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_NOLFS</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_NOMEM</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_NOTADB</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_NOTFOUND</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_NOTICE</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_NOTICE_RECOVER_ROLLBACK</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_NOTICE_RECOVER_WAL</a></li>
|
|
<li><a href='#SQLITE_BLOB'>SQLITE_NULL</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_OK</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_OK_LOAD_PERMANENTLY</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_OK_SYMLINK</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_AUTOPROXY</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_CREATE</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_DELETEONCLOSE</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_EXCLUSIVE</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_FULLMUTEX</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_MAIN_DB</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_MAIN_JOURNAL</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_MEMORY</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_NOFOLLOW</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_NOMUTEX</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_PRIVATECACHE</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_READONLY</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_READWRITE</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_SHAREDCACHE</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_SUBJOURNAL</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_SUPER_JOURNAL</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_TEMP_DB</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_TEMP_JOURNAL</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_TRANSIENT_DB</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_URI</a></li>
|
|
<li><a href='#SQLITE_OPEN_AUTOPROXY'>SQLITE_OPEN_WAL</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_PERM</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_PRAGMA</a></li>
|
|
<li><a href='#sqlitepreparenormalize'>SQLITE_PREPARE_NORMALIZE</a></li>
|
|
<li><a href='#sqlitepreparenovtab'>SQLITE_PREPARE_NO_VTAB</a></li>
|
|
<li><a href='#sqlitepreparepersistent'>SQLITE_PREPARE_PERSISTENT</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_PROTOCOL</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_RANGE</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_READ</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_READONLY</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_CANTINIT</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_CANTLOCK</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_DBMOVED</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_DIRECTORY</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_RECOVERY</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_READONLY_ROLLBACK</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_RECURSIVE</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_REINDEX</a></li>
|
|
<li><a href='#SQLITE_FAIL'>SQLITE_REPLACE</a></li>
|
|
<li><a href='#SQLITE_FAIL'>SQLITE_ROLLBACK</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_ROW</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_SAVEPOINT</a></li>
|
|
<li><a href='#sqlitescanstatest'>SQLITE_SCANSTAT_EST</a></li>
|
|
<li><a href='#sqlitescanstatexplain'>SQLITE_SCANSTAT_EXPLAIN</a></li>
|
|
<li><a href='#sqlitescanstatname'>SQLITE_SCANSTAT_NAME</a></li>
|
|
<li><a href='#sqlitescanstatnloop'>SQLITE_SCANSTAT_NLOOP</a></li>
|
|
<li><a href='#sqlitescanstatnvisit'>SQLITE_SCANSTAT_NVISIT</a></li>
|
|
<li><a href='#sqlitescanstatselectid'>SQLITE_SCANSTAT_SELECTID</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_SCHEMA</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_SELECT</a></li>
|
|
<li><a href='#SQLITE_SERIALIZE_NOCOPY'>SQLITE_SERIALIZE_NOCOPY</a></li>
|
|
<li><a href='#SQLITE_SHM_EXCLUSIVE'>SQLITE_SHM_EXCLUSIVE</a></li>
|
|
<li><a href='#SQLITE_SHM_EXCLUSIVE'>SQLITE_SHM_LOCK</a></li>
|
|
<li><a href='#SQLITE_SHM_NLOCK'>SQLITE_SHM_NLOCK</a></li>
|
|
<li><a href='#SQLITE_SHM_EXCLUSIVE'>SQLITE_SHM_SHARED</a></li>
|
|
<li><a href='#SQLITE_SHM_EXCLUSIVE'>SQLITE_SHM_UNLOCK</a></li>
|
|
<li><a href='#SQLITE_SOURCE_ID'>SQLITE_SOURCE_ID</a></li>
|
|
<li><a href='#SQLITE_STATIC'>SQLITE_STATIC</a></li>
|
|
<li><a href='#sqlitestatusmalloccount'>SQLITE_STATUS_MALLOC_COUNT</a></li>
|
|
<li><a href='#sqlitestatusmallocsize'>SQLITE_STATUS_MALLOC_SIZE</a></li>
|
|
<li><a href='#sqlitestatusmemoryused'>SQLITE_STATUS_MEMORY_USED</a></li>
|
|
<li><a href='#sqlitestatuspagecacheoverflow'>SQLITE_STATUS_PAGECACHE_OVERFLOW</a></li>
|
|
<li><a href='#sqlitestatuspagecachesize'>SQLITE_STATUS_PAGECACHE_SIZE</a></li>
|
|
<li><a href='#sqlitestatuspagecacheused'>SQLITE_STATUS_PAGECACHE_USED</a></li>
|
|
<li><a href='#sqlitestatusparserstack'>SQLITE_STATUS_PARSER_STACK</a></li>
|
|
<li><a href='#sqlitestatusscratchoverflow'>SQLITE_STATUS_SCRATCH_OVERFLOW</a></li>
|
|
<li><a href='#sqlitestatusscratchsize'>SQLITE_STATUS_SCRATCH_SIZE</a></li>
|
|
<li><a href='#sqlitestatusscratchused'>SQLITE_STATUS_SCRATCH_USED</a></li>
|
|
<li><a href='#sqlitestmtstatusautoindex'>SQLITE_STMTSTATUS_AUTOINDEX</a></li>
|
|
<li><a href='#sqlitestmtstatusfullscanstep'>SQLITE_STMTSTATUS_FULLSCAN_STEP</a></li>
|
|
<li><a href='#sqlitestmtstatusmemused'>SQLITE_STMTSTATUS_MEMUSED</a></li>
|
|
<li><a href='#sqlitestmtstatusreprepare'>SQLITE_STMTSTATUS_REPREPARE</a></li>
|
|
<li><a href='#sqlitestmtstatusrun'>SQLITE_STMTSTATUS_RUN</a></li>
|
|
<li><a href='#sqlitestmtstatussort'>SQLITE_STMTSTATUS_SORT</a></li>
|
|
<li><a href='#sqlitestmtstatusvmstep'>SQLITE_STMTSTATUS_VM_STEP</a></li>
|
|
<li><a href='#sqlitesubtype'>SQLITE_SUBTYPE</a></li>
|
|
<li><a href='#SQLITE_SYNC_DATAONLY'>SQLITE_SYNC_DATAONLY</a></li>
|
|
<li><a href='#SQLITE_SYNC_DATAONLY'>SQLITE_SYNC_FULL</a></li>
|
|
<li><a href='#SQLITE_SYNC_DATAONLY'>SQLITE_SYNC_NORMAL</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ALWAYS</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ASSERT</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_BITVEC_TEST</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_BYTEORDER</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_EXPLAIN_STMT</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_FAULT_INSTALL</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_FIRST</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_IMPOSTER</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_INTERNAL_FUNCTIONS</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ISINIT</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ISKEYWORD</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_LAST</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_LOCALTIME_FAULT</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_NEVER_CORRUPT</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_OPTIMIZATIONS</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PARSER_COVERAGE</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PENDING_BYTE</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PRNG_RESET</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PRNG_RESTORE</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PRNG_SAVE</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_PRNG_SEED</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_RESERVE</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_RESULT_INTREAL</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_SCRATCHMALLOC</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_SORTER_MMAP</a></li>
|
|
<li><a href='#SQLITE_TESTCTRL_ALWAYS'>SQLITE_TESTCTRL_VDBE_COVERAGE</a></li>
|
|
<li><a href='#SQLITE_BLOB'>SQLITE_TEXT</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_TOOBIG</a></li>
|
|
<li><a href='#SQLITE_TRACE'>SQLITE_TRACE</a></li>
|
|
<li><a href='#sqlitetraceclose'>SQLITE_TRACE_CLOSE</a></li>
|
|
<li><a href='#sqlitetraceprofile'>SQLITE_TRACE_PROFILE</a></li>
|
|
<li><a href='#sqlitetracerow'>SQLITE_TRACE_ROW</a></li>
|
|
<li><a href='#sqlitetracestmt'>SQLITE_TRACE_STMT</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_TRANSACTION</a></li>
|
|
<li><a href='#SQLITE_STATIC'>SQLITE_TRANSIENT</a></li>
|
|
<li><a href='#SQLITE_ALTER_TABLE'>SQLITE_UPDATE</a></li>
|
|
<li><a href='#SQLITE_ANY'>SQLITE_UTF16</a></li>
|
|
<li><a href='#SQLITE_ANY'>SQLITE_UTF16BE</a></li>
|
|
<li><a href='#SQLITE_ANY'>SQLITE_UTF16LE</a></li>
|
|
<li><a href='#SQLITE_ANY'>SQLITE_UTF16_ALIGNED</a></li>
|
|
<li><a href='#SQLITE_ANY'>SQLITE_UTF8</a></li>
|
|
<li><a href='#SQLITE_SOURCE_ID'>SQLITE_VERSION</a></li>
|
|
<li><a href='#SQLITE_SOURCE_ID'>SQLITE_VERSION_NUMBER</a></li>
|
|
<li><a href='#sqlitevtabconstraintsupport'>SQLITE_VTAB_CONSTRAINT_SUPPORT</a></li>
|
|
<li><a href='#sqlitevtabdirectonly'>SQLITE_VTAB_DIRECTONLY</a></li>
|
|
<li><a href='#sqlitevtabinnocuous'>SQLITE_VTAB_INNOCUOUS</a></li>
|
|
<li><a href='#SQLITE_ABORT'>SQLITE_WARNING</a></li>
|
|
<li><a href='#SQLITE_ABORT_ROLLBACK'>SQLITE_WARNING_AUTOINDEX</a></li>
|
|
<li><a href='#SQLITE_WIN32_DATA_DIRECTORY_TYPE'>SQLITE_WIN32_DATA_DIRECTORY_TYPE</a></li>
|
|
<li><a href='#SQLITE_WIN32_DATA_DIRECTORY_TYPE'>SQLITE_WIN32_TEMP_DIRECTORY_TYPE</a></li>
|
|
</ul>
|
|
</div>
|
|
<hr>
|
|
|
|
<h2>List Of Functions:</h2>
|
|
<p>Note: Functions marked with "<small><i>(exp)</i></small>"
|
|
are <a href="capi3ref.html">experimental</a> and functions whose names are
|
|
<s>struck through</s> are <a href="capi3ref.html">deprecated</a>.</p>
|
|
<!-- number of functions: 272 -->
|
|
<!-- number of deprecated functions: 7 -->
|
|
<!-- number of experimental functions: 0 -->
|
|
<div class='columns' style='columns: 15em auto;'>
|
|
<ul style='padding-top:0;'>
|
|
<li><a href='#sqlite3_aggregate_context'>sqlite3_aggregate_context</a></li>
|
|
<li><s>sqlite3_aggregate_count</s></li>
|
|
<li><a href='#sqlite3_auto_extension'>sqlite3_auto_extension</a></li>
|
|
<li><a href='#sqlite3backupfinish'>sqlite3_backup_finish</a></li>
|
|
<li><a href='#sqlite3backupinit'>sqlite3_backup_init</a></li>
|
|
<li><a href='#sqlite3backuppagecount'>sqlite3_backup_pagecount</a></li>
|
|
<li><a href='#sqlite3backupremaining'>sqlite3_backup_remaining</a></li>
|
|
<li><a href='#sqlite3backupstep'>sqlite3_backup_step</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_blob</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_blob64</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_double</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_int</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_int64</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_null</a></li>
|
|
<li><a href='#sqlite3_bind_parameter_count'>sqlite3_bind_parameter_count</a></li>
|
|
<li><a href='#sqlite3_bind_parameter_index'>sqlite3_bind_parameter_index</a></li>
|
|
<li><a href='#sqlite3_bind_parameter_name'>sqlite3_bind_parameter_name</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_pointer</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text16</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text64</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_value</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_zeroblob</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_zeroblob64</a></li>
|
|
<li><a href='#sqlite3_blob_bytes'>sqlite3_blob_bytes</a></li>
|
|
<li><a href='#sqlite3_blob_close'>sqlite3_blob_close</a></li>
|
|
<li><a href='#sqlite3_blob_open'>sqlite3_blob_open</a></li>
|
|
<li><a href='#sqlite3_blob_read'>sqlite3_blob_read</a></li>
|
|
<li><a href='#sqlite3_blob_reopen'>sqlite3_blob_reopen</a></li>
|
|
<li><a href='#sqlite3_blob_write'>sqlite3_blob_write</a></li>
|
|
<li><a href='#sqlite3_busy_handler'>sqlite3_busy_handler</a></li>
|
|
<li><a href='#sqlite3_busy_timeout'>sqlite3_busy_timeout</a></li>
|
|
<li><a href='#sqlite3_cancel_auto_extension'>sqlite3_cancel_auto_extension</a></li>
|
|
<li><a href='#sqlite3_changes'>sqlite3_changes</a></li>
|
|
<li><a href='#sqlite3_clear_bindings'>sqlite3_clear_bindings</a></li>
|
|
<li><a href='#sqlite3_close'>sqlite3_close</a></li>
|
|
<li><a href='#sqlite3_close'>sqlite3_close_v2</a></li>
|
|
<li><a href='#sqlite3_collation_needed'>sqlite3_collation_needed</a></li>
|
|
<li><a href='#sqlite3_collation_needed'>sqlite3_collation_needed16</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_blob</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_bytes</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_bytes16</a></li>
|
|
<li><a href='#sqlite3_column_count'>sqlite3_column_count</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_database_name</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_database_name16</a></li>
|
|
<li><a href='#sqlite3_column_decltype'>sqlite3_column_decltype</a></li>
|
|
<li><a href='#sqlite3_column_decltype'>sqlite3_column_decltype16</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_double</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_int</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_int64</a></li>
|
|
<li><a href='#sqlite3_column_name'>sqlite3_column_name</a></li>
|
|
<li><a href='#sqlite3_column_name'>sqlite3_column_name16</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_origin_name</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_origin_name16</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_table_name</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_table_name16</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_text</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_text16</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_type</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_value</a></li>
|
|
<li><a href='#sqlite3_commit_hook'>sqlite3_commit_hook</a></li>
|
|
<li><a href='#sqlite3_compileoption_get'>sqlite3_compileoption_get</a></li>
|
|
<li><a href='#sqlite3_compileoption_get'>sqlite3_compileoption_used</a></li>
|
|
<li><a href='#sqlite3_complete'>sqlite3_complete</a></li>
|
|
<li><a href='#sqlite3_complete'>sqlite3_complete16</a></li>
|
|
<li><a href='#sqlite3_config'>sqlite3_config</a></li>
|
|
<li><a href='#sqlite3_context_db_handle'>sqlite3_context_db_handle</a></li>
|
|
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation</a></li>
|
|
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation16</a></li>
|
|
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation_v2</a></li>
|
|
<li><a href='#sqlite3_create_filename'>sqlite3_create_filename</a></li>
|
|
<li><a href='#sqlite3_create_function'>sqlite3_create_function</a></li>
|
|
<li><a href='#sqlite3_create_function'>sqlite3_create_function16</a></li>
|
|
<li><a href='#sqlite3_create_function'>sqlite3_create_function_v2</a></li>
|
|
<li><a href='#sqlite3_create_module'>sqlite3_create_module</a></li>
|
|
<li><a href='#sqlite3_create_module'>sqlite3_create_module_v2</a></li>
|
|
<li><a href='#sqlite3_create_function'>sqlite3_create_window_function</a></li>
|
|
<li><a href='#sqlite3_data_count'>sqlite3_data_count</a></li>
|
|
<li><a href='#sqlite3_database_file_object'>sqlite3_database_file_object</a></li>
|
|
<li><a href='#sqlite3_db_cacheflush'>sqlite3_db_cacheflush</a></li>
|
|
<li><a href='#sqlite3_db_config'>sqlite3_db_config</a></li>
|
|
<li><a href='#sqlite3_db_filename'>sqlite3_db_filename</a></li>
|
|
<li><a href='#sqlite3_db_handle'>sqlite3_db_handle</a></li>
|
|
<li><a href='#sqlite3_db_mutex'>sqlite3_db_mutex</a></li>
|
|
<li><a href='#sqlite3_db_readonly'>sqlite3_db_readonly</a></li>
|
|
<li><a href='#sqlite3_db_release_memory'>sqlite3_db_release_memory</a></li>
|
|
<li><a href='#sqlite3_db_status'>sqlite3_db_status</a></li>
|
|
<li><a href='#sqlite3_declare_vtab'>sqlite3_declare_vtab</a></li>
|
|
<li><a href='#sqlite3_deserialize'>sqlite3_deserialize</a></li>
|
|
<li><a href='#sqlite3_drop_modules'>sqlite3_drop_modules</a></li>
|
|
<li><a href='#sqlite3_enable_load_extension'>sqlite3_enable_load_extension</a></li>
|
|
<li><a href='#sqlite3_enable_shared_cache'>sqlite3_enable_shared_cache</a></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_errcode</a></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_errmsg</a></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_errmsg16</a></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_errstr</a></li>
|
|
<li><a href='#sqlite3_exec'>sqlite3_exec</a></li>
|
|
<li><a href='#sqlite3_expanded_sql'>sqlite3_expanded_sql</a></li>
|
|
<li><s>sqlite3_expired</s></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_extended_errcode</a></li>
|
|
<li><a href='#sqlite3_extended_result_codes'>sqlite3_extended_result_codes</a></li>
|
|
<li><a href='#sqlite3_file_control'>sqlite3_file_control</a></li>
|
|
<li><a href='#sqlite3_filename_database'>sqlite3_filename_database</a></li>
|
|
<li><a href='#sqlite3_filename_database'>sqlite3_filename_journal</a></li>
|
|
<li><a href='#sqlite3_filename_database'>sqlite3_filename_wal</a></li>
|
|
<li><a href='#sqlite3_finalize'>sqlite3_finalize</a></li>
|
|
<li><a href='#sqlite3_free'>sqlite3_free</a></li>
|
|
<li><a href='#sqlite3_create_filename'>sqlite3_free_filename</a></li>
|
|
<li><a href='#sqlite3_free_table'>sqlite3_free_table</a></li>
|
|
<li><a href='#sqlite3_get_autocommit'>sqlite3_get_autocommit</a></li>
|
|
<li><a href='#sqlite3_get_auxdata'>sqlite3_get_auxdata</a></li>
|
|
<li><a href='#sqlite3_free_table'>sqlite3_get_table</a></li>
|
|
<li><s>sqlite3_global_recover</s></li>
|
|
<li><a href='#sqlite3_hard_heap_limit64'>sqlite3_hard_heap_limit64</a></li>
|
|
<li><a href='#sqlite3_initialize'>sqlite3_initialize</a></li>
|
|
<li><a href='#sqlite3_interrupt'>sqlite3_interrupt</a></li>
|
|
<li><a href='#sqlite3_keyword_check'>sqlite3_keyword_check</a></li>
|
|
<li><a href='#sqlite3_keyword_check'>sqlite3_keyword_count</a></li>
|
|
<li><a href='#sqlite3_keyword_check'>sqlite3_keyword_name</a></li>
|
|
<li><a href='#sqlite3_last_insert_rowid'>sqlite3_last_insert_rowid</a></li>
|
|
<li><a href='#sqlite3_libversion'>sqlite3_libversion</a></li>
|
|
<li><a href='#sqlite3_libversion'>sqlite3_libversion_number</a></li>
|
|
<li><a href='#sqlite3_limit'>sqlite3_limit</a></li>
|
|
<li><a href='#sqlite3_load_extension'>sqlite3_load_extension</a></li>
|
|
<li><a href='#sqlite3_log'>sqlite3_log</a></li>
|
|
<li><a href='#sqlite3_free'>sqlite3_malloc</a></li>
|
|
<li><a href='#sqlite3_free'>sqlite3_malloc64</a></li>
|
|
<li><s>sqlite3_memory_alarm</s></li>
|
|
<li><a href='#sqlite3_memory_highwater'>sqlite3_memory_highwater</a></li>
|
|
<li><a href='#sqlite3_memory_highwater'>sqlite3_memory_used</a></li>
|
|
<li><a href='#sqlite3_mprintf'>sqlite3_mprintf</a></li>
|
|
<li><a href='#sqlite3_free'>sqlite3_msize</a></li>
|
|
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_alloc</a></li>
|
|
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_enter</a></li>
|
|
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_free</a></li>
|
|
<li><a href='#sqlite3_mutex_held'>sqlite3_mutex_held</a></li>
|
|
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_leave</a></li>
|
|
<li><a href='#sqlite3_mutex_held'>sqlite3_mutex_notheld</a></li>
|
|
<li><a href='#sqlite3_mutex_alloc'>sqlite3_mutex_try</a></li>
|
|
<li><a href='#sqlite3_next_stmt'>sqlite3_next_stmt</a></li>
|
|
<li><a href='#sqlite3_expanded_sql'>sqlite3_normalized_sql</a></li>
|
|
<li><a href='#sqlite3_open'>sqlite3_open</a></li>
|
|
<li><a href='#sqlite3_open'>sqlite3_open16</a></li>
|
|
<li><a href='#sqlite3_open'>sqlite3_open_v2</a></li>
|
|
<li><a href='#sqlite3_initialize'>sqlite3_os_end</a></li>
|
|
<li><a href='#sqlite3_initialize'>sqlite3_os_init</a></li>
|
|
<li><a href='#sqlite3_overload_function'>sqlite3_overload_function</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare16</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v2</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v3</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v2</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v3</a></li>
|
|
<li><a href='#sqlite3_preupdate_count'>sqlite3_preupdate_count</a></li>
|
|
<li><a href='#sqlite3_preupdate_count'>sqlite3_preupdate_depth</a></li>
|
|
<li><a href='#sqlite3_preupdate_count'>sqlite3_preupdate_hook</a></li>
|
|
<li><a href='#sqlite3_preupdate_count'>sqlite3_preupdate_new</a></li>
|
|
<li><a href='#sqlite3_preupdate_count'>sqlite3_preupdate_old</a></li>
|
|
<li><a href='#sqlite3_profile'>sqlite3_profile</a></li>
|
|
<li><a href='#sqlite3_progress_handler'>sqlite3_progress_handler</a></li>
|
|
<li><a href='#sqlite3_randomness'>sqlite3_randomness</a></li>
|
|
<li><a href='#sqlite3_free'>sqlite3_realloc</a></li>
|
|
<li><a href='#sqlite3_free'>sqlite3_realloc64</a></li>
|
|
<li><a href='#sqlite3_release_memory'>sqlite3_release_memory</a></li>
|
|
<li><a href='#sqlite3_reset'>sqlite3_reset</a></li>
|
|
<li><a href='#sqlite3_reset_auto_extension'>sqlite3_reset_auto_extension</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_blob</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_blob64</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_double</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error16</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_code</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_nomem</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_toobig</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_int</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_int64</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_null</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_pointer</a></li>
|
|
<li><a href='#sqlite3_result_subtype'>sqlite3_result_subtype</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16be</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16le</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text64</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_value</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_zeroblob</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_zeroblob64</a></li>
|
|
<li><a href='#sqlite3_commit_hook'>sqlite3_rollback_hook</a></li>
|
|
<li><a href='#sqlite3_serialize'>sqlite3_serialize</a></li>
|
|
<li><a href='#sqlite3_set_authorizer'>sqlite3_set_authorizer</a></li>
|
|
<li><a href='#sqlite3_get_auxdata'>sqlite3_set_auxdata</a></li>
|
|
<li><a href='#sqlite3_set_last_insert_rowid'>sqlite3_set_last_insert_rowid</a></li>
|
|
<li><a href='#sqlite3_initialize'>sqlite3_shutdown</a></li>
|
|
<li><a href='#sqlite3_sleep'>sqlite3_sleep</a></li>
|
|
<li><a href='#sqlite3_snapshot_cmp'>sqlite3_snapshot_cmp</a></li>
|
|
<li><a href='#sqlite3_snapshot_free'>sqlite3_snapshot_free</a></li>
|
|
<li><a href='#sqlite3_snapshot_get'>sqlite3_snapshot_get</a></li>
|
|
<li><a href='#sqlite3_snapshot_open'>sqlite3_snapshot_open</a></li>
|
|
<li><a href='#sqlite3_snapshot_recover'>sqlite3_snapshot_recover</a></li>
|
|
<li><a href='#sqlite3_mprintf'>sqlite3_snprintf</a></li>
|
|
<li><s>sqlite3_soft_heap_limit</s></li>
|
|
<li><a href='#sqlite3_hard_heap_limit64'>sqlite3_soft_heap_limit64</a></li>
|
|
<li><a href='#sqlite3_libversion'>sqlite3_sourceid</a></li>
|
|
<li><a href='#sqlite3_expanded_sql'>sqlite3_sql</a></li>
|
|
<li><a href='#sqlite3_status'>sqlite3_status</a></li>
|
|
<li><a href='#sqlite3_status'>sqlite3_status64</a></li>
|
|
<li><a href='#sqlite3_step'>sqlite3_step</a></li>
|
|
<li><a href='#sqlite3_stmt_busy'>sqlite3_stmt_busy</a></li>
|
|
<li><a href='#sqlite3_stmt_isexplain'>sqlite3_stmt_isexplain</a></li>
|
|
<li><a href='#sqlite3_stmt_readonly'>sqlite3_stmt_readonly</a></li>
|
|
<li><a href='#sqlite3_stmt_scanstatus'>sqlite3_stmt_scanstatus</a></li>
|
|
<li><a href='#sqlite3_stmt_scanstatus_reset'>sqlite3_stmt_scanstatus_reset</a></li>
|
|
<li><a href='#sqlite3_stmt_status'>sqlite3_stmt_status</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_append</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_appendall</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_appendchar</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_appendf</a></li>
|
|
<li><a href='#sqlite3_str_errcode'>sqlite3_str_errcode</a></li>
|
|
<li><a href='#sqlite3_str_finish'>sqlite3_str_finish</a></li>
|
|
<li><a href='#sqlite3_str_errcode'>sqlite3_str_length</a></li>
|
|
<li><a href='#sqlite3_str_new'>sqlite3_str_new</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_reset</a></li>
|
|
<li><a href='#sqlite3_str_errcode'>sqlite3_str_value</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_vappendf</a></li>
|
|
<li><a href='#sqlite3_strglob'>sqlite3_strglob</a></li>
|
|
<li><a href='#sqlite3_stricmp'>sqlite3_stricmp</a></li>
|
|
<li><a href='#sqlite3_strlike'>sqlite3_strlike</a></li>
|
|
<li><a href='#sqlite3_stricmp'>sqlite3_strnicmp</a></li>
|
|
<li><a href='#sqlite3_system_errno'>sqlite3_system_errno</a></li>
|
|
<li><a href='#sqlite3_table_column_metadata'>sqlite3_table_column_metadata</a></li>
|
|
<li><a href='#sqlite3_test_control'>sqlite3_test_control</a></li>
|
|
<li><s>sqlite3_thread_cleanup</s></li>
|
|
<li><a href='#sqlite3_threadsafe'>sqlite3_threadsafe</a></li>
|
|
<li><a href='#sqlite3_total_changes'>sqlite3_total_changes</a></li>
|
|
<li><a href='#sqlite3_profile'>sqlite3_trace</a></li>
|
|
<li><a href='#sqlite3_trace_v2'>sqlite3_trace_v2</a></li>
|
|
<li><s>sqlite3_transfer_bindings</s></li>
|
|
<li><a href='#sqlite3_unlock_notify'>sqlite3_unlock_notify</a></li>
|
|
<li><a href='#sqlite3_update_hook'>sqlite3_update_hook</a></li>
|
|
<li><a href='#sqlite3_uri_boolean'>sqlite3_uri_boolean</a></li>
|
|
<li><a href='#sqlite3_uri_boolean'>sqlite3_uri_int64</a></li>
|
|
<li><a href='#sqlite3_uri_boolean'>sqlite3_uri_key</a></li>
|
|
<li><a href='#sqlite3_uri_boolean'>sqlite3_uri_parameter</a></li>
|
|
<li><a href='#sqlite3_user_data'>sqlite3_user_data</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_blob</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_bytes</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_bytes16</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_double</a></li>
|
|
<li><a href='#sqlite3_value_dup'>sqlite3_value_dup</a></li>
|
|
<li><a href='#sqlite3_value_dup'>sqlite3_value_free</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_frombind</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_int</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_int64</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_nochange</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_numeric_type</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_pointer</a></li>
|
|
<li><a href='#sqlite3_value_subtype'>sqlite3_value_subtype</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_text</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16be</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16le</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_type</a></li>
|
|
<li><a href='#sqlite3_libversion'>sqlite3_version</a></li>
|
|
<li><a href='#sqlite3_vfs_find'>sqlite3_vfs_find</a></li>
|
|
<li><a href='#sqlite3_vfs_find'>sqlite3_vfs_register</a></li>
|
|
<li><a href='#sqlite3_vfs_find'>sqlite3_vfs_unregister</a></li>
|
|
<li><a href='#sqlite3_mprintf'>sqlite3_vmprintf</a></li>
|
|
<li><a href='#sqlite3_mprintf'>sqlite3_vsnprintf</a></li>
|
|
<li><a href='#sqlite3_vtab_collation'>sqlite3_vtab_collation</a></li>
|
|
<li><a href='#sqlite3_vtab_config'>sqlite3_vtab_config</a></li>
|
|
<li><a href='#sqlite3_vtab_nochange'>sqlite3_vtab_nochange</a></li>
|
|
<li><a href='#sqlite3_vtab_on_conflict'>sqlite3_vtab_on_conflict</a></li>
|
|
<li><a href='#sqlite3_wal_autocheckpoint'>sqlite3_wal_autocheckpoint</a></li>
|
|
<li><a href='#sqlite3_wal_checkpoint'>sqlite3_wal_checkpoint</a></li>
|
|
<li><a href='#sqlite3_wal_checkpoint_v2'>sqlite3_wal_checkpoint_v2</a></li>
|
|
<li><a href='#sqlite3_wal_hook'>sqlite3_wal_hook</a></li>
|
|
<li><a href='#sqlite3_win32_set_directory'>sqlite3_win32_set_directory</a></li>
|
|
<li><a href='#sqlite3_win32_set_directory'>sqlite3_win32_set_directory16</a></li>
|
|
<li><a href='#sqlite3_win32_set_directory'>sqlite3_win32_set_directory8</a></li>
|
|
</ul>
|
|
</div>
|
|
<hr>
|
|
<a name="SQLITE_INDEX_SCAN_UNIQUE"></a>
|
|
<h2>Virtual Table Scan Flags</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */
|
|
</pre></blockquote>
|
|
<p>
|
|
Virtual table implementations are allowed to set the
|
|
<a href="#sqlite3_index_info">sqlite3_index_info</a>.idxFlags field to some combination of
|
|
these bits.
|
|
</p><hr><a name="SQLITE_SERIALIZE_NOCOPY"></a>
|
|
<h2>Flags for sqlite3_serialize</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */
|
|
</pre></blockquote>
|
|
<p>
|
|
Zero or more of the following constants can be OR-ed together for
|
|
the F argument to <a href="#sqlite3_serialize">sqlite3_serialize(D,S,P,F)</a>.</p>
|
|
|
|
<p>SQLITE_SERIALIZE_NOCOPY means that <a href="#sqlite3_serialize">sqlite3_serialize()</a> will return
|
|
a pointer to contiguous in-memory database that it is currently using,
|
|
without making a copy of the database. If SQLite is not currently using
|
|
a contiguous in-memory database, then this option causes
|
|
<a href="#sqlite3_serialize">sqlite3_serialize()</a> to return a NULL pointer. SQLite will only be
|
|
using a contiguous in-memory database if it has been initialized by a
|
|
prior call to <a href="#sqlite3_deserialize">sqlite3_deserialize()</a>.
|
|
</p><hr><a name="SQLITE_SHM_NLOCK"></a>
|
|
<h2>Maximum xShmLock index</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_SHM_NLOCK 8
|
|
</pre></blockquote>
|
|
<p>
|
|
The xShmLock method on <a href="#sqlite3_io_methods">sqlite3_io_methods</a> may use values
|
|
between 0 and this upper bound as its "offset" argument.
|
|
The SQLite core will never attempt to acquire or release a
|
|
lock outside of this range
|
|
</p><hr><a name="sqlite3_api_routines"></a>
|
|
<h2>Loadable Extension Thunk</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_api_routines sqlite3_api_routines;
|
|
</pre></blockquote>
|
|
<p>
|
|
A pointer to the opaque sqlite3_api_routines structure is passed as
|
|
the third parameter to entry points of <a href="loadext.html">loadable extensions</a>. This
|
|
structure must be typedefed in order to work around compiler warnings
|
|
on some platforms.
|
|
</p><hr><a name="sqlite3_backup"></a>
|
|
<h2>Online Backup Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_backup sqlite3_backup;
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_backup object records state information about an ongoing
|
|
online backup operation. The sqlite3_backup object is created by
|
|
a call to <a href="#sqlite3backupinit">sqlite3_backup_init()</a> and is destroyed by a call to
|
|
<a href="#sqlite3backupfinish">sqlite3_backup_finish()</a>.</p>
|
|
|
|
<p>See Also: <a href="backup.html">Using the SQLite Online Backup API</a>
|
|
</p><hr><a name="sqlite3_context"></a>
|
|
<h2>SQL Function Context Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_context sqlite3_context;
|
|
</pre></blockquote>
|
|
<p>
|
|
The context in which an SQL function executes is stored in an
|
|
sqlite3_context object. A pointer to an sqlite3_context object
|
|
is always first parameter to <a href="appfunc.html">application-defined SQL functions</a>.
|
|
The application-defined SQL function implementation will pass this
|
|
pointer through into calls to <a href="#sqlite3_result_blob">sqlite3_result()</a>,
|
|
<a href="#sqlite3_aggregate_context">sqlite3_aggregate_context()</a>, <a href="#sqlite3_user_data">sqlite3_user_data()</a>,
|
|
<a href="#sqlite3_context_db_handle">sqlite3_context_db_handle()</a>, <a href="#sqlite3_get_auxdata">sqlite3_get_auxdata()</a>,
|
|
and/or <a href="#sqlite3_get_auxdata">sqlite3_set_auxdata()</a>.
|
|
</p><div class='columns' style='columns: 17em auto;'>
|
|
<ul style='padding-top:0;'>
|
|
<li><a href='#sqlite3_aggregate_context'>sqlite3_aggregate_context</a></li>
|
|
<li><a href='#sqlite3_context_db_handle'>sqlite3_context_db_handle</a></li>
|
|
<li><a href='#sqlite3_get_auxdata'>sqlite3_get_auxdata</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_blob</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_blob64</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_double</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error16</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_code</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_nomem</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_error_toobig</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_int</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_int64</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_null</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_pointer</a></li>
|
|
<li><a href='#sqlite3_result_subtype'>sqlite3_result_subtype</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16be</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text16le</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_text64</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_value</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_zeroblob</a></li>
|
|
<li><a href='#sqlite3_result_blob'>sqlite3_result_zeroblob64</a></li>
|
|
<li><a href='#sqlite3_get_auxdata'>sqlite3_set_auxdata</a></li>
|
|
<li><a href='#sqlite3_user_data'>sqlite3_user_data</a></li>
|
|
</ul>
|
|
</div>
|
|
</p>
|
|
<hr><a name="sqlite3_data_directory"></a>
|
|
<h2>Name Of The Folder Holding Database Files</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
SQLITE_EXTERN char *sqlite3_data_directory;
|
|
</pre></blockquote>
|
|
<p>
|
|
If this global variable is made to point to a string which is
|
|
the name of a folder (a.k.a. directory), then all database files
|
|
specified with a relative pathname and created or accessed by
|
|
SQLite when using a built-in windows <a href="#sqlite3_vfs">VFS</a> will be assumed
|
|
to be relative to that directory. If this variable is a NULL
|
|
pointer, then SQLite assumes that all database files specified
|
|
with a relative pathname are relative to the current directory
|
|
for the process. Only the windows VFS makes use of this global
|
|
variable; it is ignored by the unix VFS.</p>
|
|
|
|
<p>Changing the value of this variable while a database connection is
|
|
open can result in a corrupt database.</p>
|
|
|
|
<p>It is not safe to read or modify this variable in more than one
|
|
thread at a time. It is not safe to read or modify this variable
|
|
if a <a href="#sqlite3">database connection</a> is being used at the same time in a separate
|
|
thread.
|
|
It is intended that this variable be set once
|
|
as part of process initialization and before any SQLite interface
|
|
routines have been called and that this variable remain unchanged
|
|
thereafter.</p>
|
|
|
|
<p>The <a href="pragma.html#pragma_data_store_directory">data_store_directory pragma</a> may modify this variable and cause
|
|
it to point to memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>. Furthermore,
|
|
the <a href="pragma.html#pragma_data_store_directory">data_store_directory pragma</a> always assumes that any string
|
|
that this variable points to is held in memory obtained from
|
|
<a href="#sqlite3_free">sqlite3_malloc</a> and the pragma may attempt to free that memory
|
|
using <a href="#sqlite3_free">sqlite3_free</a>.
|
|
Hence, if this variable is modified directly, either it should be
|
|
made NULL or made to point to memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>
|
|
or else the use of the <a href="pragma.html#pragma_data_store_directory">data_store_directory pragma</a> should be avoided.
|
|
</p><hr><a name="sqlite3_file"></a>
|
|
<h2>OS Interface Open File Handle</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_file sqlite3_file;
|
|
struct sqlite3_file {
|
|
const struct sqlite3_io_methods *pMethods; /* Methods for an open file */
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
An <a href="#sqlite3_file">sqlite3_file</a> object represents an open file in the
|
|
<a href="#sqlite3_vfs">OS interface layer</a>. Individual OS interface
|
|
implementations will
|
|
want to subclass this object by appending additional fields
|
|
for their own use. The pMethods entry is a pointer to an
|
|
<a href="#sqlite3_io_methods">sqlite3_io_methods</a> object that defines methods for performing
|
|
I/O operations on the open file.
|
|
</p><hr><a name="sqlite3_index_info"></a>
|
|
<h2>Virtual Table Indexing Information</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
struct sqlite3_index_info {
|
|
/* Inputs */
|
|
int nConstraint; /* Number of entries in aConstraint */
|
|
struct sqlite3_index_constraint {
|
|
int iColumn; /* Column constrained. -1 for ROWID */
|
|
unsigned char op; /* Constraint operator */
|
|
unsigned char usable; /* True if this constraint is usable */
|
|
int iTermOffset; /* Used internally - xBestIndex should ignore */
|
|
} *aConstraint; /* Table of WHERE clause constraints */
|
|
int nOrderBy; /* Number of terms in the ORDER BY clause */
|
|
struct sqlite3_index_orderby {
|
|
int iColumn; /* Column number */
|
|
unsigned char desc; /* True for DESC. False for ASC. */
|
|
} *aOrderBy; /* The ORDER BY clause */
|
|
/* Outputs */
|
|
struct sqlite3_index_constraint_usage {
|
|
int argvIndex; /* if >0, constraint is part of argv to xFilter */
|
|
unsigned char omit; /* Do not code a test for this constraint */
|
|
} *aConstraintUsage;
|
|
int idxNum; /* Number used to identify the index */
|
|
char *idxStr; /* String, possibly obtained from sqlite3_malloc */
|
|
int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */
|
|
int orderByConsumed; /* True if output is already ordered */
|
|
double estimatedCost; /* Estimated cost of using this index */
|
|
/* Fields below are only available in SQLite 3.8.2 and later */
|
|
sqlite3_int64 estimatedRows; /* Estimated number of rows returned */
|
|
/* Fields below are only available in SQLite 3.9.0 and later */
|
|
int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */
|
|
/* Fields below are only available in SQLite 3.10.0 and later */
|
|
sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_index_info structure and its substructures is used as part
|
|
of the <a href="vtab.html">virtual table</a> interface to
|
|
pass information into and receive the reply from the <a href="vtab.html#xbestindex">xBestIndex</a>
|
|
method of a <a href="#sqlite3_module">virtual table module</a>. The fields under **Inputs** are the
|
|
inputs to xBestIndex and are read-only. xBestIndex inserts its
|
|
results into the **Outputs** fields.</p>
|
|
|
|
<p>The aConstraint[] array records WHERE clause constraints of the form:</p>
|
|
|
|
<p><blockquote>column OP expr</blockquote></p>
|
|
|
|
<p>where OP is =, <, <=, >, or >=. The particular operator is
|
|
stored in aConstraint[].op using one of the
|
|
<a href="#SQLITE_INDEX_CONSTRAINT_EQ">SQLITE_INDEX_CONSTRAINT_ values</a>.
|
|
The index of the column is stored in
|
|
aConstraint[].iColumn. aConstraint[].usable is TRUE if the
|
|
expr on the right-hand side can be evaluated (and thus the constraint
|
|
is usable) and false if it cannot.</p>
|
|
|
|
<p>The optimizer automatically inverts terms of the form "expr OP column"
|
|
and makes other simplifications to the WHERE clause in an attempt to
|
|
get as many WHERE clause terms into the form shown above as possible.
|
|
The aConstraint[] array only reports WHERE clause terms that are
|
|
relevant to the particular virtual table being queried.</p>
|
|
|
|
<p>Information about the ORDER BY clause is stored in aOrderBy[].
|
|
Each term of aOrderBy records a column of the ORDER BY clause.</p>
|
|
|
|
<p>The colUsed field indicates which columns of the virtual table may be
|
|
required by the current scan. Virtual table columns are numbered from
|
|
zero in the order in which they appear within the CREATE TABLE statement
|
|
passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
|
|
the corresponding bit is set within the colUsed mask if the column may be
|
|
required by SQLite. If the table has at least 64 columns and any column
|
|
to the right of the first 63 is required, then bit 63 of colUsed is also
|
|
set. In other words, column iCol may be required if the expression
|
|
(colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
|
|
non-zero.</p>
|
|
|
|
<p>The <a href="vtab.html#xbestindex">xBestIndex</a> method must fill aConstraintUsage[] with information
|
|
about what parameters to pass to xFilter. If argvIndex>0 then
|
|
the right-hand side of the corresponding aConstraint[] is evaluated
|
|
and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit
|
|
is true, then the constraint is assumed to be fully handled by the
|
|
virtual table and might not be checked again by the byte code. The
|
|
aConstraintUsage[].omit flag is an optimization hint. When the omit flag
|
|
is left in its default setting of false, the constraint will always be
|
|
checked separately in byte code. If the omit flag is change to true, then
|
|
the constraint may or may not be checked in byte code. In other words,
|
|
when the omit flag is true there is no guarantee that the constraint will
|
|
not be checked again using byte code.</p>
|
|
|
|
<p>The idxNum and idxPtr values are recorded and passed into the
|
|
<a href="vtab.html#xfilter">xFilter</a> method.
|
|
<a href="#sqlite3_free">sqlite3_free()</a> is used to free idxPtr if and only if
|
|
needToFreeIdxPtr is true.</p>
|
|
|
|
<p>The orderByConsumed means that output from <a href="vtab.html#xfilter">xFilter</a>/<a href="vtab.html#xnext">xNext</a> will occur in
|
|
the correct order to satisfy the ORDER BY clause so that no separate
|
|
sorting step is required.</p>
|
|
|
|
<p>The estimatedCost value is an estimate of the cost of a particular
|
|
strategy. A cost of N indicates that the cost of the strategy is similar
|
|
to a linear scan of an SQLite table with N rows. A cost of log(N)
|
|
indicates that the expense of the operation is similar to that of a
|
|
binary search on a unique indexed field of an SQLite table with N rows.</p>
|
|
|
|
<p>The estimatedRows value is an estimate of the number of rows that
|
|
will be returned by the strategy.</p>
|
|
|
|
<p>The xBestIndex method may optionally populate the idxFlags field with a
|
|
mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
|
|
SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
|
|
assumes that the strategy may visit at most one row.</p>
|
|
|
|
<p>Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
|
|
SQLite also assumes that if a call to the xUpdate() method is made as
|
|
part of the same statement to delete or update a virtual table row and the
|
|
implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
|
|
any database changes. In other words, if the xUpdate() returns
|
|
SQLITE_CONSTRAINT, the database contents must be exactly as they were
|
|
before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
|
|
set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
|
|
the xUpdate method are automatically rolled back by SQLite.</p>
|
|
|
|
<p>IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
|
|
structure for SQLite <a href="releaselog/3_8_2.html">version 3.8.2</a> (2013-12-06).
|
|
If a virtual table extension is
|
|
used with an SQLite version earlier than 3.8.2, the results of attempting
|
|
to read or write the estimatedRows field are undefined (but are likely
|
|
to include crashing the application). The estimatedRows field should
|
|
therefore only be used if <a href="#sqlite3_libversion">sqlite3_libversion_number()</a> returns a
|
|
value greater than or equal to 3008002. Similarly, the idxFlags field
|
|
was added for <a href="releaselog/3_9_0.html">version 3.9.0</a> (2015-10-14).
|
|
It may therefore only be used if
|
|
sqlite3_libversion_number() returns a value greater than or equal to
|
|
3009000.
|
|
</p><hr><a name="sqlite3_io_methods"></a>
|
|
<h2>OS Interface File Virtual Methods Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_io_methods sqlite3_io_methods;
|
|
struct sqlite3_io_methods {
|
|
int iVersion;
|
|
int (*xClose)(sqlite3_file*);
|
|
int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
|
|
int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
|
|
int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
|
|
int (*xSync)(sqlite3_file*, int flags);
|
|
int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
|
|
int (*xLock)(sqlite3_file*, int);
|
|
int (*xUnlock)(sqlite3_file*, int);
|
|
int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
|
|
int (*xFileControl)(sqlite3_file*, int op, void *pArg);
|
|
int (*xSectorSize)(sqlite3_file*);
|
|
int (*xDeviceCharacteristics)(sqlite3_file*);
|
|
/* Methods above are valid for version 1 */
|
|
int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
|
|
int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
|
|
void (*xShmBarrier)(sqlite3_file*);
|
|
int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
|
|
/* Methods above are valid for version 2 */
|
|
int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
|
|
int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
|
|
/* Methods above are valid for version 3 */
|
|
/* Additional methods may be added in future releases */
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
Every file opened by the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> method populates an
|
|
<a href="#sqlite3_file">sqlite3_file</a> object (or, more commonly, a subclass of the
|
|
<a href="#sqlite3_file">sqlite3_file</a> object) with a pointer to an instance of this object.
|
|
This object defines the methods used to perform various operations
|
|
against the open file represented by the <a href="#sqlite3_file">sqlite3_file</a> object.</p>
|
|
|
|
<p>If the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> method sets the sqlite3_file.pMethods element
|
|
to a non-NULL pointer, then the sqlite3_io_methods.xClose method
|
|
may be invoked even if the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> reported that it failed. The
|
|
only way to prevent a call to xClose following a failed <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a>
|
|
is for the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> to set the sqlite3_file.pMethods element
|
|
to NULL.</p>
|
|
|
|
<p>The flags argument to xSync may be one of <a href="#SQLITE_SYNC_DATAONLY">SQLITE_SYNC_NORMAL</a> or
|
|
<a href="#SQLITE_SYNC_DATAONLY">SQLITE_SYNC_FULL</a>. The first choice is the normal fsync().
|
|
The second choice is a Mac OS X style fullsync. The <a href="#SQLITE_SYNC_DATAONLY">SQLITE_SYNC_DATAONLY</a>
|
|
flag may be ORed in to indicate that only the data of the file
|
|
and not its inode needs to be synced.</p>
|
|
|
|
<p>The integer values to xLock() and xUnlock() are one of
|
|
<ul>
|
|
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_NONE</a>,
|
|
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_SHARED</a>,
|
|
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_RESERVED</a>,
|
|
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_PENDING</a>, or
|
|
<li> <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_EXCLUSIVE</a>.
|
|
</ul>
|
|
xLock() increases the lock. xUnlock() decreases the lock.
|
|
The xCheckReservedLock() method checks whether any database connection,
|
|
either in this process or in some other process, is holding a RESERVED,
|
|
PENDING, or EXCLUSIVE lock on the file. It returns true
|
|
if such a lock exists and false otherwise.</p>
|
|
|
|
<p>The xFileControl() method is a generic interface that allows custom
|
|
VFS implementations to directly control an open file using the
|
|
<a href="#sqlite3_file_control">sqlite3_file_control()</a> interface. The second "op" argument is an
|
|
integer opcode. The third argument is a generic pointer intended to
|
|
point to a structure that may contain arguments or space in which to
|
|
write return values. Potential uses for xFileControl() might be
|
|
functions to enable blocking locks with timeouts, to change the
|
|
locking strategy (for example to use dot-file locks), to inquire
|
|
about the status of a lock, or to break stale locks. The SQLite
|
|
core reserves all opcodes less than 100 for its own use.
|
|
A <a href="#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE">list of opcodes</a> less than 100 is available.
|
|
Applications that define a custom xFileControl method should use opcodes
|
|
greater than 100 to avoid conflicts. VFS implementations should
|
|
return <a href="#SQLITE_ABORT">SQLITE_NOTFOUND</a> for file control opcodes that they do not
|
|
recognize.</p>
|
|
|
|
<p>The xSectorSize() method returns the sector size of the
|
|
device that underlies the file. The sector size is the
|
|
minimum write that can be performed without disturbing
|
|
other bytes in the file. The xDeviceCharacteristics()
|
|
method returns a bit vector describing behaviors of the
|
|
underlying device:</p>
|
|
|
|
<p><ul>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC512</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC1K</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC2K</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC4K</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC8K</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC16K</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC32K</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_ATOMIC64K</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_SAFE_APPEND</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_SEQUENTIAL</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_POWERSAFE_OVERWRITE</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_IMMUTABLE</a>
|
|
<li> <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_BATCH_ATOMIC</a>
|
|
</ul></p>
|
|
|
|
<p>The SQLITE_IOCAP_ATOMIC property means that all writes of
|
|
any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
|
|
mean that writes of blocks that are nnn bytes in size and
|
|
are aligned to an address which is an integer multiple of
|
|
nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
|
|
that when data is appended to a file, the data is appended
|
|
first then the size of the file is extended, never the other
|
|
way around. The SQLITE_IOCAP_SEQUENTIAL property means that
|
|
information is written to disk in the same order as calls
|
|
to xWrite().</p>
|
|
|
|
<p>If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
|
|
in the unread portions of the buffer with zeros. A VFS that
|
|
fails to zero-fill short reads might seem to work. However,
|
|
failure to zero-fill short reads will eventually lead to
|
|
database corruption.
|
|
</p><hr><a name="sqlite3_mem_methods"></a>
|
|
<h2>Memory Allocation Routines</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_mem_methods sqlite3_mem_methods;
|
|
struct sqlite3_mem_methods {
|
|
void *(*xMalloc)(int); /* Memory allocation function */
|
|
void (*xFree)(void*); /* Free a prior allocation */
|
|
void *(*xRealloc)(void*,int); /* Resize an allocation */
|
|
int (*xSize)(void*); /* Return the size of an allocation */
|
|
int (*xRoundup)(int); /* Round up request size to allocation size */
|
|
int (*xInit)(void*); /* Initialize the memory allocator */
|
|
void (*xShutdown)(void*); /* Deinitialize the memory allocator */
|
|
void *pAppData; /* Argument to xInit() and xShutdown() */
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
An instance of this object defines the interface between SQLite
|
|
and low-level memory allocation routines.</p>
|
|
|
|
<p>This object is used in only one place in the SQLite interface.
|
|
A pointer to an instance of this object is the argument to
|
|
<a href="#sqlite3_config">sqlite3_config()</a> when the configuration option is
|
|
<a href="#sqliteconfigmalloc">SQLITE_CONFIG_MALLOC</a> or <a href="#sqliteconfiggetmalloc">SQLITE_CONFIG_GETMALLOC</a>.
|
|
By creating an instance of this object
|
|
and passing it to <a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigmalloc">SQLITE_CONFIG_MALLOC</a>)
|
|
during configuration, an application can specify an alternative
|
|
memory allocation subsystem for SQLite to use for all of its
|
|
dynamic memory needs.</p>
|
|
|
|
<p>Note that SQLite comes with several <a href="malloc.html#altalloc">built-in memory allocators</a>
|
|
that are perfectly adequate for the overwhelming majority of applications
|
|
and that this object is only useful to a tiny minority of applications
|
|
with specialized memory allocation requirements. This object is
|
|
also used during testing of SQLite in order to specify an alternative
|
|
memory allocator that simulates memory out-of-memory conditions in
|
|
order to verify that SQLite recovers gracefully from such
|
|
conditions.</p>
|
|
|
|
<p>The xMalloc, xRealloc, and xFree methods must work like the
|
|
malloc(), realloc() and free() functions from the standard C library.
|
|
SQLite guarantees that the second argument to
|
|
xRealloc is always a value returned by a prior call to xRoundup.</p>
|
|
|
|
<p>xSize should return the allocated size of a memory allocation
|
|
previously obtained from xMalloc or xRealloc. The allocated size
|
|
is always at least as big as the requested size but may be larger.</p>
|
|
|
|
<p>The xRoundup method returns what would be the allocated size of
|
|
a memory allocation given a particular requested size. Most memory
|
|
allocators round up memory allocations at least to the next multiple
|
|
of 8. Some allocators round up to a larger multiple or to a power of 2.
|
|
Every memory allocation request coming in through <a href="#sqlite3_free">sqlite3_malloc()</a>
|
|
or <a href="#sqlite3_free">sqlite3_realloc()</a> first calls xRoundup. If xRoundup returns 0,
|
|
that causes the corresponding memory allocation to fail.</p>
|
|
|
|
<p>The xInit method initializes the memory allocator. For example,
|
|
it might allocate any required mutexes or initialize internal data
|
|
structures. The xShutdown method is invoked (indirectly) by
|
|
<a href="#sqlite3_initialize">sqlite3_shutdown()</a> and should deallocate any resources acquired
|
|
by xInit. The pAppData pointer is used as the only parameter to
|
|
xInit and xShutdown.</p>
|
|
|
|
<p>SQLite holds the <a href="#SQLITE_MUTEX_FAST">SQLITE_MUTEX_STATIC_MAIN</a> mutex when it invokes
|
|
the xInit method, so the xInit method need not be threadsafe. The
|
|
xShutdown method is only called from <a href="#sqlite3_initialize">sqlite3_shutdown()</a> so it does
|
|
not need to be threadsafe either. For all other methods, SQLite
|
|
holds the <a href="#SQLITE_MUTEX_FAST">SQLITE_MUTEX_STATIC_MEM</a> mutex as long as the
|
|
<a href="#sqliteconfigmemstatus">SQLITE_CONFIG_MEMSTATUS</a> configuration option is turned on (which
|
|
it is by default) and so the methods are automatically serialized.
|
|
However, if <a href="#sqliteconfigmemstatus">SQLITE_CONFIG_MEMSTATUS</a> is disabled, then the other
|
|
methods must be threadsafe or else make their own arrangements for
|
|
serialization.</p>
|
|
|
|
<p>SQLite will never invoke xInit() more than once without an intervening
|
|
call to xShutdown().
|
|
</p><hr><a name="sqlite3_mutex"></a>
|
|
<h2>Mutex Handle</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_mutex sqlite3_mutex;
|
|
</pre></blockquote>
|
|
<p>
|
|
The mutex module within SQLite defines <a href="#sqlite3_mutex">sqlite3_mutex</a> to be an
|
|
abstract type for a mutex object. The SQLite core never looks
|
|
at the internal representation of an <a href="#sqlite3_mutex">sqlite3_mutex</a>. It only
|
|
deals with pointers to the <a href="#sqlite3_mutex">sqlite3_mutex</a> object.</p>
|
|
|
|
<p>Mutexes are created using <a href="#sqlite3_mutex_alloc">sqlite3_mutex_alloc()</a>.
|
|
</p><hr><a name="sqlite3_mutex_methods"></a>
|
|
<h2>Mutex Methods Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
|
|
struct sqlite3_mutex_methods {
|
|
int (*xMutexInit)(void);
|
|
int (*xMutexEnd)(void);
|
|
sqlite3_mutex *(*xMutexAlloc)(int);
|
|
void (*xMutexFree)(sqlite3_mutex *);
|
|
void (*xMutexEnter)(sqlite3_mutex *);
|
|
int (*xMutexTry)(sqlite3_mutex *);
|
|
void (*xMutexLeave)(sqlite3_mutex *);
|
|
int (*xMutexHeld)(sqlite3_mutex *);
|
|
int (*xMutexNotheld)(sqlite3_mutex *);
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
An instance of this structure defines the low-level routines
|
|
used to allocate and use mutexes.</p>
|
|
|
|
<p>Usually, the default mutex implementations provided by SQLite are
|
|
sufficient, however the application has the option of substituting a custom
|
|
implementation for specialized deployments or systems for which SQLite
|
|
does not provide a suitable implementation. In this case, the application
|
|
creates and populates an instance of this structure to pass
|
|
to sqlite3_config() along with the <a href="#sqliteconfigmutex">SQLITE_CONFIG_MUTEX</a> option.
|
|
Additionally, an instance of this structure can be used as an
|
|
output variable when querying the system for the current mutex
|
|
implementation, using the <a href="#sqliteconfiggetmutex">SQLITE_CONFIG_GETMUTEX</a> option.</p>
|
|
|
|
<p>The xMutexInit method defined by this structure is invoked as
|
|
part of system initialization by the sqlite3_initialize() function.
|
|
The xMutexInit routine is called by SQLite exactly once for each
|
|
effective call to <a href="#sqlite3_initialize">sqlite3_initialize()</a>.</p>
|
|
|
|
<p>The xMutexEnd method defined by this structure is invoked as
|
|
part of system shutdown by the sqlite3_shutdown() function. The
|
|
implementation of this method is expected to release all outstanding
|
|
resources obtained by the mutex methods implementation, especially
|
|
those obtained by the xMutexInit method. The xMutexEnd()
|
|
interface is invoked exactly once for each call to <a href="#sqlite3_initialize">sqlite3_shutdown()</a>.</p>
|
|
|
|
<p>The remaining seven methods defined by this structure (xMutexAlloc,
|
|
xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
|
|
xMutexNotheld) implement the following interfaces (respectively):</p>
|
|
|
|
<p><ul>
|
|
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_alloc()</a> </li>
|
|
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_free()</a> </li>
|
|
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_enter()</a> </li>
|
|
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_try()</a> </li>
|
|
<li> <a href="#sqlite3_mutex_alloc">sqlite3_mutex_leave()</a> </li>
|
|
<li> <a href="#sqlite3_mutex_held">sqlite3_mutex_held()</a> </li>
|
|
<li> <a href="#sqlite3_mutex_held">sqlite3_mutex_notheld()</a> </li>
|
|
</ul></p>
|
|
|
|
<p>The only difference is that the public sqlite3_XXX functions enumerated
|
|
above silently ignore any invocations that pass a NULL pointer instead
|
|
of a valid mutex handle. The implementations of the methods defined
|
|
by this structure are not required to handle this case. The results
|
|
of passing a NULL pointer instead of a valid mutex handle are undefined
|
|
(i.e. it is acceptable to provide an implementation that segfaults if
|
|
it is passed a NULL pointer).</p>
|
|
|
|
<p>The xMutexInit() method must be threadsafe. It must be harmless to
|
|
invoke xMutexInit() multiple times within the same process and without
|
|
intervening calls to xMutexEnd(). Second and subsequent calls to
|
|
xMutexInit() must be no-ops.</p>
|
|
|
|
<p>xMutexInit() must not use SQLite memory allocation (<a href="#sqlite3_free">sqlite3_malloc()</a>
|
|
and its associates). Similarly, xMutexAlloc() must not use SQLite memory
|
|
allocation for a static mutex. However xMutexAlloc() may use SQLite
|
|
memory allocation for a fast or recursive mutex.</p>
|
|
|
|
<p>SQLite will invoke the xMutexEnd() method when <a href="#sqlite3_initialize">sqlite3_shutdown()</a> is
|
|
called, but only if the prior call to xMutexInit returned SQLITE_OK.
|
|
If xMutexInit fails in any way, it is expected to clean up after itself
|
|
prior to returning.
|
|
</p><hr><a name="sqlite3_pcache"></a>
|
|
<h2>Custom Page Cache Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_pcache sqlite3_pcache;
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_pcache type is opaque. It is implemented by
|
|
the pluggable module. The SQLite core has no knowledge of
|
|
its size or internal structure and never deals with the
|
|
sqlite3_pcache object except by holding and passing pointers
|
|
to the object.</p>
|
|
|
|
<p>See <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> for additional information.
|
|
</p><hr><a name="sqlite3_pcache_page"></a>
|
|
<h2>Custom Page Cache Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_pcache_page sqlite3_pcache_page;
|
|
struct sqlite3_pcache_page {
|
|
void *pBuf; /* The content of the page */
|
|
void *pExtra; /* Extra information associated with the page */
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_pcache_page object represents a single page in the
|
|
page cache. The page cache will allocate instances of this
|
|
object. Various methods of the page cache use pointers to instances
|
|
of this object as parameters or as their return value.</p>
|
|
|
|
<p>See <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> for additional information.
|
|
</p><hr><a name="sqlite3_temp_directory"></a>
|
|
<h2>Name Of The Folder Holding Temporary Files</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
SQLITE_EXTERN char *sqlite3_temp_directory;
|
|
</pre></blockquote>
|
|
<p>
|
|
If this global variable is made to point to a string which is
|
|
the name of a folder (a.k.a. directory), then all temporary files
|
|
created by SQLite when using a built-in <a href="#sqlite3_vfs">VFS</a>
|
|
will be placed in that directory. If this variable
|
|
is a NULL pointer, then SQLite performs a search for an appropriate
|
|
temporary file directory.</p>
|
|
|
|
<p>Applications are strongly discouraged from using this global variable.
|
|
It is required to set a temporary folder on Windows Runtime (WinRT).
|
|
But for all other platforms, it is highly recommended that applications
|
|
neither read nor write this variable. This global variable is a relic
|
|
that exists for backwards compatibility of legacy applications and should
|
|
be avoided in new projects.</p>
|
|
|
|
<p>It is not safe to read or modify this variable in more than one
|
|
thread at a time. It is not safe to read or modify this variable
|
|
if a <a href="#sqlite3">database connection</a> is being used at the same time in a separate
|
|
thread.
|
|
It is intended that this variable be set once
|
|
as part of process initialization and before any SQLite interface
|
|
routines have been called and that this variable remain unchanged
|
|
thereafter.</p>
|
|
|
|
<p>The <a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a> may modify this variable and cause
|
|
it to point to memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>. Furthermore,
|
|
the <a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a> always assumes that any string
|
|
that this variable points to is held in memory obtained from
|
|
<a href="#sqlite3_free">sqlite3_malloc</a> and the pragma may attempt to free that memory
|
|
using <a href="#sqlite3_free">sqlite3_free</a>.
|
|
Hence, if this variable is modified directly, either it should be
|
|
made NULL or made to point to memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>
|
|
or else the use of the <a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a> should be avoided.
|
|
Except when requested by the <a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a>, SQLite
|
|
does not free the memory that sqlite3_temp_directory points to. If
|
|
the application wants that memory to be freed, it must do
|
|
so itself, taking care to only do so after all <a href="#sqlite3">database connection</a>
|
|
objects have been destroyed.</p>
|
|
|
|
<p><b>Note to Windows Runtime users:</b> The temporary directory must be set
|
|
prior to calling <a href="#sqlite3_open">sqlite3_open</a> or <a href="#sqlite3_open">sqlite3_open_v2</a>. Otherwise, various
|
|
features that require the use of temporary files may fail. Here is an
|
|
example of how to do this using C++ with the Windows Runtime:</p>
|
|
|
|
<p><blockquote><pre>
|
|
LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
|
|
TemporaryFolder->Path->Data();
|
|
char zPathBuf[MAX_PATH + 1];
|
|
memset(zPathBuf, 0, sizeof(zPathBuf));
|
|
WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
|
|
NULL, NULL);
|
|
sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
|
|
</pre></blockquote>
|
|
</p><hr><a name="sqlite3_vfs"></a>
|
|
<h2>OS Interface Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_vfs sqlite3_vfs;
|
|
typedef void (*sqlite3_syscall_ptr)(void);
|
|
struct sqlite3_vfs {
|
|
int iVersion; /* Structure version number (currently 3) */
|
|
int szOsFile; /* Size of subclassed sqlite3_file */
|
|
int mxPathname; /* Maximum file pathname length */
|
|
sqlite3_vfs *pNext; /* Next registered VFS */
|
|
const char *zName; /* Name of this virtual file system */
|
|
void *pAppData; /* Pointer to application-specific data */
|
|
int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
|
|
int flags, int *pOutFlags);
|
|
int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
|
|
int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
|
|
int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
|
|
void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
|
|
void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
|
|
void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
|
|
void (*xDlClose)(sqlite3_vfs*, void*);
|
|
int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
|
|
int (*xSleep)(sqlite3_vfs*, int microseconds);
|
|
int (*xCurrentTime)(sqlite3_vfs*, double*);
|
|
int (*xGetLastError)(sqlite3_vfs*, int, char *);
|
|
/*
|
|
** The methods above are in version 1 of the sqlite_vfs object
|
|
** definition. Those that follow are added in version 2 or later
|
|
*/
|
|
int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
|
|
/*
|
|
** The methods above are in versions 1 and 2 of the sqlite_vfs object.
|
|
** Those below are for version 3 and greater.
|
|
*/
|
|
int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
|
|
sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
|
|
const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
|
|
/*
|
|
** The methods above are in versions 1 through 3 of the sqlite_vfs object.
|
|
** New fields may be appended in future versions. The iVersion
|
|
** value will increment whenever this happens.
|
|
*/
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
An instance of the sqlite3_vfs object defines the interface between
|
|
the SQLite core and the underlying operating system. The "vfs"
|
|
in the name of the object stands for "virtual file system". See
|
|
the <a href="vfs.html">VFS documentation</a> for further information.</p>
|
|
|
|
<p>The VFS interface is sometimes extended by adding new methods onto
|
|
the end. Each time such an extension occurs, the iVersion field
|
|
is incremented. The iVersion value started out as 1 in
|
|
SQLite <a href="releaselog/3_5_0.html">version 3.5.0</a> on 2007-09-04, then increased to 2
|
|
with SQLite <a href="releaselog/3_7_0.html">version 3.7.0</a> on 2010-07-21, and then increased
|
|
to 3 with SQLite <a href="releaselog/3_7_6.html">version 3.7.6</a> on 2011-04-12. Additional fields
|
|
may be appended to the sqlite3_vfs object and the iVersion value
|
|
may increase again in future versions of SQLite.
|
|
Note that due to an oversight, the structure
|
|
of the sqlite3_vfs object changed in the transition from
|
|
SQLite <a href="releaselog/3_5_9.html">version 3.5.9</a> to <a href="releaselog/3_6_0.html">version 3.6.0</a> on 2008-07-16
|
|
and yet the iVersion field was not increased.</p>
|
|
|
|
<p>The szOsFile field is the size of the subclassed <a href="#sqlite3_file">sqlite3_file</a>
|
|
structure used by this VFS. mxPathname is the maximum length of
|
|
a pathname in this VFS.</p>
|
|
|
|
<p>Registered sqlite3_vfs objects are kept on a linked list formed by
|
|
the pNext pointer. The <a href="#sqlite3_vfs_find">sqlite3_vfs_register()</a>
|
|
and <a href="#sqlite3_vfs_find">sqlite3_vfs_unregister()</a> interfaces manage this list
|
|
in a thread-safe way. The <a href="#sqlite3_vfs_find">sqlite3_vfs_find()</a> interface
|
|
searches the list. Neither the application code nor the VFS
|
|
implementation should use the pNext pointer.</p>
|
|
|
|
<p>The pNext field is the only field in the sqlite3_vfs
|
|
structure that SQLite will ever modify. SQLite will only access
|
|
or modify this field while holding a particular static mutex.
|
|
The application should never modify anything within the sqlite3_vfs
|
|
object once the object has been registered.</p>
|
|
|
|
<p>The zName field holds the name of the VFS module. The name must
|
|
be unique across all VFS modules.</p>
|
|
|
|
<p><a name="sqlite3vfsxopen"></a>
|
|
|
|
SQLite guarantees that the zFilename parameter to xOpen
|
|
is either a NULL pointer or string obtained
|
|
from xFullPathname() with an optional suffix added.
|
|
If a suffix is added to the zFilename parameter, it will
|
|
consist of a single "-" character followed by no more than
|
|
11 alphanumeric and/or "-" characters.
|
|
SQLite further guarantees that
|
|
the string will be valid and unchanged until xClose() is
|
|
called. Because of the previous sentence,
|
|
the <a href="#sqlite3_file">sqlite3_file</a> can safely store a pointer to the
|
|
filename if it needs to remember the filename for some reason.
|
|
If the zFilename parameter to xOpen is a NULL pointer then xOpen
|
|
must invent its own temporary name for the file. Whenever the
|
|
xFilename parameter is NULL it will also be the case that the
|
|
flags parameter will include <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_DELETEONCLOSE</a>.</p>
|
|
|
|
<p>The flags argument to xOpen() includes all bits set in
|
|
the flags argument to <a href="#sqlite3_open">sqlite3_open_v2()</a>. Or if <a href="#sqlite3_open">sqlite3_open()</a>
|
|
or <a href="#sqlite3_open">sqlite3_open16()</a> is used, then flags includes at least
|
|
<a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READWRITE</a> | <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_CREATE</a>.
|
|
If xOpen() opens a file read-only then it sets *pOutFlags to
|
|
include <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READONLY</a>. Other bits in *pOutFlags may be set.</p>
|
|
|
|
<p>SQLite will also add one of the following flags to the xOpen()
|
|
call, depending on the object being opened:</p>
|
|
|
|
<p><ul>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_MAIN_DB</a>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_MAIN_JOURNAL</a>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_TEMP_DB</a>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_TEMP_JOURNAL</a>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_TRANSIENT_DB</a>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SUBJOURNAL</a>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SUPER_JOURNAL</a>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_WAL</a>
|
|
</ul></p>
|
|
|
|
<p>The file I/O implementation can use the object type flags to
|
|
change the way it deals with files. For example, an application
|
|
that does not care about crash recovery or rollback might make
|
|
the open of a journal file a no-op. Writes to this journal would
|
|
also be no-ops, and any attempt to read the journal would return
|
|
SQLITE_IOERR. Or the implementation might recognize that a database
|
|
file will be doing page-aligned sector reads and writes in a random
|
|
order and set up its I/O subsystem accordingly.</p>
|
|
|
|
<p>SQLite might also add one of the following flags to the xOpen method:</p>
|
|
|
|
<p><ul>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_DELETEONCLOSE</a>
|
|
<li> <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_EXCLUSIVE</a>
|
|
</ul></p>
|
|
|
|
<p>The <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_DELETEONCLOSE</a> flag means the file should be
|
|
deleted when it is closed. The <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_DELETEONCLOSE</a>
|
|
will be set for TEMP databases and their journals, transient
|
|
databases, and subjournals.</p>
|
|
|
|
<p>The <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_EXCLUSIVE</a> flag is always used in conjunction
|
|
with the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_CREATE</a> flag, which are both directly
|
|
analogous to the O_EXCL and O_CREAT flags of the POSIX open()
|
|
API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
|
|
SQLITE_OPEN_CREATE, is used to indicate that file should always
|
|
be created, and that it is an error if it already exists.
|
|
It is <i>not</i> used to indicate the file should be opened
|
|
for exclusive access.</p>
|
|
|
|
<p>At least szOsFile bytes of memory are allocated by SQLite
|
|
to hold the <a href="#sqlite3_file">sqlite3_file</a> structure passed as the third
|
|
argument to xOpen. The xOpen method does not have to
|
|
allocate the structure; it should just fill it in. Note that
|
|
the xOpen method must set the sqlite3_file.pMethods to either
|
|
a valid <a href="#sqlite3_io_methods">sqlite3_io_methods</a> object or to NULL. xOpen must do
|
|
this even if the open fails. SQLite expects that the sqlite3_file.pMethods
|
|
element will be valid after xOpen returns regardless of the success
|
|
or failure of the xOpen call.</p>
|
|
|
|
<p><a name="sqlite3vfsxaccess"></a>
|
|
|
|
The flags argument to xAccess() may be <a href="#SQLITE_ACCESS_EXISTS">SQLITE_ACCESS_EXISTS</a>
|
|
to test for the existence of a file, or <a href="#SQLITE_ACCESS_EXISTS">SQLITE_ACCESS_READWRITE</a> to
|
|
test whether a file is readable and writable, or <a href="#SQLITE_ACCESS_EXISTS">SQLITE_ACCESS_READ</a>
|
|
to test whether a file is at least readable. The SQLITE_ACCESS_READ
|
|
flag is never actually used and is not implemented in the built-in
|
|
VFSes of SQLite. The file is named by the second argument and can be a
|
|
directory. The xAccess method returns <a href="#SQLITE_ABORT">SQLITE_OK</a> on success or some
|
|
non-zero error code if there is an I/O error or if the name of
|
|
the file given in the second argument is illegal. If SQLITE_OK
|
|
is returned, then non-zero or zero is written into *pResOut to indicate
|
|
whether or not the file is accessible.</p>
|
|
|
|
<p>SQLite will always allocate at least mxPathname+1 bytes for the
|
|
output buffer xFullPathname. The exact size of the output buffer
|
|
is also passed as a parameter to both methods. If the output buffer
|
|
is not large enough, <a href="#SQLITE_ABORT">SQLITE_CANTOPEN</a> should be returned. Since this is
|
|
handled as a fatal error by SQLite, vfs implementations should endeavor
|
|
to prevent this by setting mxPathname to a sufficiently large value.</p>
|
|
|
|
<p>The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
|
|
interfaces are not strictly a part of the filesystem, but they are
|
|
included in the VFS structure for completeness.
|
|
The xRandomness() function attempts to return nBytes bytes
|
|
of good-quality randomness into zOut. The return value is
|
|
the actual number of bytes of randomness obtained.
|
|
The xSleep() method causes the calling thread to sleep for at
|
|
least the number of microseconds given. The xCurrentTime()
|
|
method returns a Julian Day Number for the current date and time as
|
|
a floating point value.
|
|
The xCurrentTimeInt64() method returns, as an integer, the Julian
|
|
Day Number multiplied by 86400000 (the number of milliseconds in
|
|
a 24-hour day).
|
|
SQLite will use the xCurrentTimeInt64() method to get the current
|
|
date and time if that method is available (if iVersion is 2 or
|
|
greater and the function pointer is not NULL) and will fall back
|
|
to xCurrentTime() if xCurrentTimeInt64() is unavailable.</p>
|
|
|
|
<p>The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
|
|
are not used by the SQLite core. These optional interfaces are provided
|
|
by some VFSes to facilitate testing of the VFS code. By overriding
|
|
system calls with functions under its control, a test program can
|
|
simulate faults and error conditions that would otherwise be difficult
|
|
or impossible to induce. The set of system calls that can be overridden
|
|
varies from one VFS to another, and from one version of the same VFS to the
|
|
next. Applications that use these interfaces must be prepared for any
|
|
or all of these interfaces to be NULL or for their behavior to change
|
|
from one release to the next. Applications must not attempt to access
|
|
any of these methods if the iVersion of the VFS is less than 3.
|
|
</p><hr><a name="sqlite3_vtab"></a>
|
|
<h2>Virtual Table Instance Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
struct sqlite3_vtab {
|
|
const sqlite3_module *pModule; /* The module for this virtual table */
|
|
int nRef; /* Number of open cursors */
|
|
char *zErrMsg; /* Error message from sqlite3_mprintf() */
|
|
/* Virtual table implementations will typically add additional fields */
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
Every <a href="#sqlite3_module">virtual table module</a> implementation uses a subclass
|
|
of this object to describe a particular instance
|
|
of the <a href="vtab.html">virtual table</a>. Each subclass will
|
|
be tailored to the specific needs of the module implementation.
|
|
The purpose of this superclass is to define certain fields that are
|
|
common to all module implementations.</p>
|
|
|
|
<p>Virtual tables methods can set an error message by assigning a
|
|
string obtained from <a href="#sqlite3_mprintf">sqlite3_mprintf()</a> to zErrMsg. The method should
|
|
take care that any prior string is freed by a call to <a href="#sqlite3_free">sqlite3_free()</a>
|
|
prior to assigning a new string to zErrMsg. After the error message
|
|
is delivered up to the client application, the string will be automatically
|
|
freed by sqlite3_free() and the zErrMsg field will be zeroed.
|
|
</p><hr><a name="sqlite3_aggregate_context"></a>
|
|
<h2>Obtain Aggregate Function Context</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
|
|
</pre></blockquote>
|
|
<p>
|
|
Implementations of aggregate SQL functions use this
|
|
routine to allocate memory for storing their state.</p>
|
|
|
|
<p>The first time the sqlite3_aggregate_context(C,N) routine is called
|
|
for a particular aggregate function, SQLite allocates
|
|
N bytes of memory, zeroes out that memory, and returns a pointer
|
|
to the new memory. On second and subsequent calls to
|
|
sqlite3_aggregate_context() for the same aggregate function instance,
|
|
the same buffer is returned. Sqlite3_aggregate_context() is normally
|
|
called once for each invocation of the xStep callback and then one
|
|
last time when the xFinal callback is invoked. When no rows match
|
|
an aggregate query, the xStep() callback of the aggregate function
|
|
implementation is never called and xFinal() is called exactly once.
|
|
In those cases, sqlite3_aggregate_context() might be called for the
|
|
first time from within xFinal().</p>
|
|
|
|
<p>The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
|
|
when first called if N is less than or equal to zero or if a memory
|
|
allocate error occurs.</p>
|
|
|
|
<p>The amount of space allocated by sqlite3_aggregate_context(C,N) is
|
|
determined by the N parameter on first successful call. Changing the
|
|
value of N in any subsequent call to sqlite3_aggregate_context() within
|
|
the same aggregate function instance will not resize the memory
|
|
allocation. Within the xFinal callback, it is customary to set
|
|
N=0 in calls to sqlite3_aggregate_context(C,N) so that no
|
|
pointless memory allocations occur.</p>
|
|
|
|
<p>SQLite automatically frees the memory allocated by
|
|
sqlite3_aggregate_context() when the aggregate query concludes.</p>
|
|
|
|
<p>The first parameter must be a copy of the
|
|
<a href="#sqlite3_context">SQL function context</a> that is the first parameter
|
|
to the xStep or xFinal callback routine that implements the aggregate
|
|
function.</p>
|
|
|
|
<p>This routine must be called from the same thread in which
|
|
the aggregate SQL function is running.
|
|
</p><hr><a name="sqlite3_auto_extension"></a>
|
|
<h2>Automatically Load Statically Linked Extensions</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_auto_extension(void(*xEntryPoint)(void));
|
|
</pre></blockquote>
|
|
<p>
|
|
This interface causes the xEntryPoint() function to be invoked for
|
|
each new <a href="#sqlite3">database connection</a> that is created. The idea here is that
|
|
xEntryPoint() is the entry point for a statically linked <a href="loadext.html">SQLite extension</a>
|
|
that is to be automatically loaded into all new database connections.</p>
|
|
|
|
<p>Even though the function prototype shows that xEntryPoint() takes
|
|
no arguments and returns void, SQLite invokes xEntryPoint() with three
|
|
arguments and expects an integer result as if the signature of the
|
|
entry point where as follows:</p>
|
|
|
|
<p><blockquote><pre>
|
|
int xEntryPoint(
|
|
sqlite3 *db,
|
|
const char **pzErrMsg,
|
|
const struct sqlite3_api_routines *pThunk
|
|
);
|
|
</pre></blockquote></p>
|
|
|
|
<p>If the xEntryPoint routine encounters an error, it should make *pzErrMsg
|
|
point to an appropriate error message (obtained from <a href="#sqlite3_mprintf">sqlite3_mprintf()</a>)
|
|
and return an appropriate <a href="rescode.html">error code</a>. SQLite ensures that *pzErrMsg
|
|
is NULL before calling the xEntryPoint(). SQLite will invoke
|
|
<a href="#sqlite3_free">sqlite3_free()</a> on *pzErrMsg after xEntryPoint() returns. If any
|
|
xEntryPoint() returns an error, the <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open16()</a>,
|
|
or <a href="#sqlite3_open">sqlite3_open_v2()</a> call that provoked the xEntryPoint() will fail.</p>
|
|
|
|
<p>Calling sqlite3_auto_extension(X) with an entry point X that is already
|
|
on the list of automatic extensions is a harmless no-op. No entry point
|
|
will be called more than once for each database connection that is opened.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_reset_auto_extension">sqlite3_reset_auto_extension()</a>
|
|
and <a href="#sqlite3_cancel_auto_extension">sqlite3_cancel_auto_extension()</a>
|
|
</p><hr><a name="sqlite3_bind_parameter_count"></a>
|
|
<h2>Number Of SQL Parameters</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_bind_parameter_count(sqlite3_stmt*);
|
|
</pre></blockquote>
|
|
<p>
|
|
This routine can be used to find the number of <a href="#sqlite3_bind_blob">SQL parameters</a>
|
|
in a <a href="#sqlite3_stmt">prepared statement</a>. SQL parameters are tokens of the
|
|
form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
|
|
placeholders for values that are <a href="#sqlite3_bind_blob">bound</a>
|
|
to the parameters at a later time.</p>
|
|
|
|
<p>This routine actually returns the index of the largest (rightmost)
|
|
parameter. For all forms except ?NNN, this will correspond to the
|
|
number of unique parameters. If parameters of the ?NNN form are used,
|
|
there may be gaps in the list.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_bind_blob">sqlite3_bind()</a>,
|
|
<a href="#sqlite3_bind_parameter_name">sqlite3_bind_parameter_name()</a>, and
|
|
<a href="#sqlite3_bind_parameter_index">sqlite3_bind_parameter_index()</a>.
|
|
</p><hr><a name="sqlite3_bind_parameter_index"></a>
|
|
<h2>Index Of A Parameter With A Given Name</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
|
|
</pre></blockquote>
|
|
<p>
|
|
Return the index of an SQL parameter given its name. The
|
|
index value returned is suitable for use as the second
|
|
parameter to <a href="#sqlite3_bind_blob">sqlite3_bind()</a>. A zero
|
|
is returned if no matching parameter is found. The parameter
|
|
name must be given in UTF-8 even if the original statement
|
|
was prepared from UTF-16 text using <a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a> or
|
|
<a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_bind_blob">sqlite3_bind()</a>,
|
|
<a href="#sqlite3_bind_parameter_count">sqlite3_bind_parameter_count()</a>, and
|
|
<a href="#sqlite3_bind_parameter_name">sqlite3_bind_parameter_name()</a>.
|
|
</p><hr><a name="sqlite3_bind_parameter_name"></a>
|
|
<h2>Name Of A Host Parameter</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_bind_parameter_name(P,N) interface returns
|
|
the name of the N-th <a href="#sqlite3_bind_blob">SQL parameter</a> in the <a href="#sqlite3_stmt">prepared statement</a> P.
|
|
SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
|
|
have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
|
|
respectively.
|
|
In other words, the initial ":" or "$" or "@" or "?"
|
|
is included as part of the name.
|
|
Parameters of the form "?" without a following integer have no name
|
|
and are referred to as "nameless" or "anonymous parameters".</p>
|
|
|
|
<p>The first host parameter has an index of 1, not 0.</p>
|
|
|
|
<p>If the value N is out of range or if the N-th parameter is
|
|
nameless, then NULL is returned. The returned string is
|
|
always in UTF-8 encoding even if the named parameter was
|
|
originally specified as UTF-16 in <a href="#sqlite3_prepare">sqlite3_prepare16()</a>,
|
|
<a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a>, or <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_bind_blob">sqlite3_bind()</a>,
|
|
<a href="#sqlite3_bind_parameter_count">sqlite3_bind_parameter_count()</a>, and
|
|
<a href="#sqlite3_bind_parameter_index">sqlite3_bind_parameter_index()</a>.
|
|
</p><hr><a name="sqlite3_blob_bytes"></a>
|
|
<h2>Return The Size Of An Open BLOB</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_blob_bytes(sqlite3_blob *);
|
|
</pre></blockquote>
|
|
<p>
|
|
Returns the size in bytes of the BLOB accessible via the
|
|
successfully opened <a href="#sqlite3_blob">BLOB handle</a> in its only argument. The
|
|
incremental blob I/O routines can only read or overwriting existing
|
|
blob content; they cannot change the size of a blob.</p>
|
|
|
|
<p>This routine only works on a <a href="#sqlite3_blob">BLOB handle</a> which has been created
|
|
by a prior successful call to <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> and which has not
|
|
been closed by <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>. Passing any other pointer in
|
|
to this routine results in undefined and probably undesirable behavior.
|
|
</p><hr><a name="sqlite3_blob_close"></a>
|
|
<h2>Close A BLOB Handle</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_blob_close(sqlite3_blob *);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function closes an open <a href="#sqlite3_blob">BLOB handle</a>. The BLOB handle is closed
|
|
unconditionally. Even if this routine returns an error code, the
|
|
handle is still closed.</p>
|
|
|
|
<p>If the blob handle being closed was opened for read-write access, and if
|
|
the database is in auto-commit mode and there are no other open read-write
|
|
blob handles or active write statements, the current transaction is
|
|
committed. If an error occurs while committing the transaction, an error
|
|
code is returned and the transaction rolled back.</p>
|
|
|
|
<p>Calling this function with an argument that is not a NULL pointer or an
|
|
open blob handle results in undefined behaviour. Calling this routine
|
|
with a null pointer (such as would be returned by a failed call to
|
|
<a href="#sqlite3_blob_open">sqlite3_blob_open()</a>) is a harmless no-op. Otherwise, if this function
|
|
is passed a valid open blob handle, the values returned by the
|
|
sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
|
|
</p><hr><a name="sqlite3_blob_open"></a>
|
|
<h2>Open A BLOB For Incremental I/O</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_blob_open(
|
|
sqlite3*,
|
|
const char *zDb,
|
|
const char *zTable,
|
|
const char *zColumn,
|
|
sqlite3_int64 iRow,
|
|
int flags,
|
|
sqlite3_blob **ppBlob
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
This interfaces opens a <a href="#sqlite3_blob">handle</a> to the BLOB located
|
|
in row iRow, column zColumn, table zTable in database zDb;
|
|
in other words, the same BLOB that would be selected by:</p>
|
|
|
|
<p><pre>
|
|
SELECT zColumn FROM zDb.zTable WHERE <a href="lang_createtable.html#rowid">rowid</a> = iRow;
|
|
</pre></p>
|
|
|
|
<p>Parameter zDb is not the filename that contains the database, but
|
|
rather the symbolic name of the database. For attached databases, this is
|
|
the name that appears after the AS keyword in the <a href="lang_attach.html">ATTACH</a> statement.
|
|
For the main database file, the database name is "main". For TEMP
|
|
tables, the database name is "temp".</p>
|
|
|
|
<p>If the flags parameter is non-zero, then the BLOB is opened for read
|
|
and write access. If the flags parameter is zero, the BLOB is opened for
|
|
read-only access.</p>
|
|
|
|
<p>On success, <a href="#SQLITE_ABORT">SQLITE_OK</a> is returned and the new <a href="#sqlite3_blob">BLOB handle</a> is stored
|
|
in *ppBlob. Otherwise an <a href="rescode.html">error code</a> is returned and, unless the error
|
|
code is SQLITE_MISUSE, *ppBlob is set to NULL. This means that, provided
|
|
the API is not misused, it is always safe to call <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>
|
|
on *ppBlob after this function it returns.</p>
|
|
|
|
<p>This function fails with SQLITE_ERROR if any of the following are true:
|
|
<ul>
|
|
<li> Database zDb does not exist,
|
|
<li> Table zTable does not exist within database zDb,
|
|
<li> Table zTable is a WITHOUT ROWID table,
|
|
<li> Column zColumn does not exist,
|
|
<li> Row iRow is not present in the table,
|
|
<li> The specified column of row iRow contains a value that is not
|
|
a TEXT or BLOB value,
|
|
<li> Column zColumn is part of an index, PRIMARY KEY or UNIQUE
|
|
constraint and the blob is being opened for read/write access,
|
|
<li> <a href="foreignkeys.html">Foreign key constraints</a> are enabled,
|
|
column zColumn is part of a <a href="foreignkeys.html#parentchild">child key</a> definition and the blob is
|
|
being opened for read/write access.
|
|
</ul></p>
|
|
|
|
<p>Unless it returns SQLITE_MISUSE, this function sets the
|
|
<a href="#sqlite3">database connection</a> error code and message accessible via
|
|
<a href="#sqlite3_errcode">sqlite3_errcode()</a> and <a href="#sqlite3_errcode">sqlite3_errmsg()</a> and related functions.</p>
|
|
|
|
<p>A BLOB referenced by sqlite3_blob_open() may be read using the
|
|
<a href="#sqlite3_blob_read">sqlite3_blob_read()</a> interface and modified by using
|
|
<a href="#sqlite3_blob_write">sqlite3_blob_write()</a>. The <a href="#sqlite3_blob">BLOB handle</a> can be moved to a
|
|
different row of the same table using the <a href="#sqlite3_blob_reopen">sqlite3_blob_reopen()</a>
|
|
interface. However, the column, table, or database of a <a href="#sqlite3_blob">BLOB handle</a>
|
|
cannot be changed after the <a href="#sqlite3_blob">BLOB handle</a> is opened.</p>
|
|
|
|
<p>If the row that a BLOB handle points to is modified by an
|
|
<a href="lang_update.html">UPDATE</a>, <a href="lang_delete.html">DELETE</a>, or by <a href="lang_conflict.html">ON CONFLICT</a> side-effects
|
|
then the BLOB handle is marked as "expired".
|
|
This is true if any column of the row is changed, even a column
|
|
other than the one the BLOB handle is open on.
|
|
Calls to <a href="#sqlite3_blob_read">sqlite3_blob_read()</a> and <a href="#sqlite3_blob_write">sqlite3_blob_write()</a> for
|
|
an expired BLOB handle fail with a return code of <a href="#SQLITE_ABORT">SQLITE_ABORT</a>.
|
|
Changes written into a BLOB prior to the BLOB expiring are not
|
|
rolled back by the expiration of the BLOB. Such changes will eventually
|
|
commit if the transaction continues to completion.</p>
|
|
|
|
<p>Use the <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> interface to determine the size of
|
|
the opened blob. The size of a blob may not be changed by this
|
|
interface. Use the <a href="lang_update.html">UPDATE</a> SQL command to change the size of a
|
|
blob.</p>
|
|
|
|
<p>The <a href="#sqlite3_bind_blob">sqlite3_bind_zeroblob()</a> and <a href="#sqlite3_result_blob">sqlite3_result_zeroblob()</a> interfaces
|
|
and the built-in <a href="lang_corefunc.html#zeroblob">zeroblob</a> SQL function may be used to create a
|
|
zero-filled blob to read or write using the incremental-blob interface.</p>
|
|
|
|
<p>To avoid a resource leak, every open <a href="#sqlite3_blob">BLOB handle</a> should eventually
|
|
be released by a call to <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>,
|
|
<a href="#sqlite3_blob_reopen">sqlite3_blob_reopen()</a>, <a href="#sqlite3_blob_read">sqlite3_blob_read()</a>,
|
|
<a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a>, <a href="#sqlite3_blob_write">sqlite3_blob_write()</a>.
|
|
</p><hr><a name="sqlite3_blob_read"></a>
|
|
<h2>Read Data From A BLOB Incrementally</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function is used to read data from an open <a href="#sqlite3_blob">BLOB handle</a> into a
|
|
caller-supplied buffer. N bytes of data are copied into buffer Z
|
|
from the open BLOB, starting at offset iOffset.</p>
|
|
|
|
<p>If offset iOffset is less than N bytes from the end of the BLOB,
|
|
<a href="#SQLITE_ABORT">SQLITE_ERROR</a> is returned and no data is read. If N or iOffset is
|
|
less than zero, <a href="#SQLITE_ABORT">SQLITE_ERROR</a> is returned and no data is read.
|
|
The size of the blob (and hence the maximum value of N+iOffset)
|
|
can be determined using the <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> interface.</p>
|
|
|
|
<p>An attempt to read from an expired <a href="#sqlite3_blob">BLOB handle</a> fails with an
|
|
error code of <a href="#SQLITE_ABORT">SQLITE_ABORT</a>.</p>
|
|
|
|
<p>On success, sqlite3_blob_read() returns SQLITE_OK.
|
|
Otherwise, an <a href="rescode.html">error code</a> or an <a href="rescode.html#extrc">extended error code</a> is returned.</p>
|
|
|
|
<p>This routine only works on a <a href="#sqlite3_blob">BLOB handle</a> which has been created
|
|
by a prior successful call to <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> and which has not
|
|
been closed by <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>. Passing any other pointer in
|
|
to this routine results in undefined and probably undesirable behavior.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_blob_write">sqlite3_blob_write()</a>.
|
|
</p><hr><a name="sqlite3_blob_reopen"></a>
|
|
<h2>Move a BLOB Handle to a New Row</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function is used to move an existing <a href="#sqlite3_blob">BLOB handle</a> so that it points
|
|
to a different row of the same database table. The new row is identified
|
|
by the rowid value passed as the second argument. Only the row can be
|
|
changed. The database, table and column on which the blob handle is open
|
|
remain the same. Moving an existing <a href="#sqlite3_blob">BLOB handle</a> to a new row is
|
|
faster than closing the existing handle and opening a new one.</p>
|
|
|
|
<p>The new row must meet the same criteria as for <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> -
|
|
it must exist and there must be either a blob or text value stored in
|
|
the nominated column. If the new row is not present in the table, or if
|
|
it does not contain a blob or text value, or if another error occurs, an
|
|
SQLite error code is returned and the blob handle is considered aborted.
|
|
All subsequent calls to <a href="#sqlite3_blob_read">sqlite3_blob_read()</a>, <a href="#sqlite3_blob_write">sqlite3_blob_write()</a> or
|
|
<a href="#sqlite3_blob_reopen">sqlite3_blob_reopen()</a> on an aborted blob handle immediately return
|
|
SQLITE_ABORT. Calling <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> on an aborted blob handle
|
|
always returns zero.</p>
|
|
|
|
<p>This function sets the database handle error code and message.
|
|
</p><hr><a name="sqlite3_blob_write"></a>
|
|
<h2>Write Data Into A BLOB Incrementally</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function is used to write data into an open <a href="#sqlite3_blob">BLOB handle</a> from a
|
|
caller-supplied buffer. N bytes of data are copied from the buffer Z
|
|
into the open BLOB, starting at offset iOffset.</p>
|
|
|
|
<p>On success, sqlite3_blob_write() returns SQLITE_OK.
|
|
Otherwise, an <a href="rescode.html">error code</a> or an <a href="rescode.html#extrc">extended error code</a> is returned.
|
|
Unless SQLITE_MISUSE is returned, this function sets the
|
|
<a href="#sqlite3">database connection</a> error code and message accessible via
|
|
<a href="#sqlite3_errcode">sqlite3_errcode()</a> and <a href="#sqlite3_errcode">sqlite3_errmsg()</a> and related functions.</p>
|
|
|
|
<p>If the <a href="#sqlite3_blob">BLOB handle</a> passed as the first argument was not opened for
|
|
writing (the flags parameter to <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> was zero),
|
|
this function returns <a href="#SQLITE_ABORT">SQLITE_READONLY</a>.</p>
|
|
|
|
<p>This function may only modify the contents of the BLOB; it is
|
|
not possible to increase the size of a BLOB using this API.
|
|
If offset iOffset is less than N bytes from the end of the BLOB,
|
|
<a href="#SQLITE_ABORT">SQLITE_ERROR</a> is returned and no data is written. The size of the
|
|
BLOB (and hence the maximum value of N+iOffset) can be determined
|
|
using the <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> interface. If N or iOffset are less
|
|
than zero <a href="#SQLITE_ABORT">SQLITE_ERROR</a> is returned and no data is written.</p>
|
|
|
|
<p>An attempt to write to an expired <a href="#sqlite3_blob">BLOB handle</a> fails with an
|
|
error code of <a href="#SQLITE_ABORT">SQLITE_ABORT</a>. Writes to the BLOB that occurred
|
|
before the <a href="#sqlite3_blob">BLOB handle</a> expired are not rolled back by the
|
|
expiration of the handle, though of course those changes might
|
|
have been overwritten by the statement that expired the BLOB handle
|
|
or by other independent statements.</p>
|
|
|
|
<p>This routine only works on a <a href="#sqlite3_blob">BLOB handle</a> which has been created
|
|
by a prior successful call to <a href="#sqlite3_blob_open">sqlite3_blob_open()</a> and which has not
|
|
been closed by <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>. Passing any other pointer in
|
|
to this routine results in undefined and probably undesirable behavior.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_blob_read">sqlite3_blob_read()</a>.
|
|
</p><hr><a name="sqlite3_busy_timeout"></a>
|
|
<h2>Set A Busy Timeout</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_busy_timeout(sqlite3*, int ms);
|
|
</pre></blockquote>
|
|
<p>
|
|
This routine sets a <a href="#sqlite3_busy_handler">busy handler</a> that sleeps
|
|
for a specified amount of time when a table is locked. The handler
|
|
will sleep multiple times until at least "ms" milliseconds of sleeping
|
|
have accumulated. After at least "ms" milliseconds of sleeping,
|
|
the handler returns 0 which causes <a href="#sqlite3_step">sqlite3_step()</a> to return
|
|
<a href="#SQLITE_ABORT">SQLITE_BUSY</a>.</p>
|
|
|
|
<p>Calling this routine with an argument less than or equal to zero
|
|
turns off all busy handlers.</p>
|
|
|
|
<p>There can only be a single busy handler for a particular
|
|
<a href="#sqlite3">database connection</a> at any given moment. If another busy handler
|
|
was defined (using <a href="#sqlite3_busy_handler">sqlite3_busy_handler()</a>) prior to calling
|
|
this routine, that other busy handler is cleared.</p>
|
|
|
|
<p>See also: <a href="pragma.html#pragma_busy_timeout">PRAGMA busy_timeout</a>
|
|
</p><hr><a name="sqlite3_cancel_auto_extension"></a>
|
|
<h2>Cancel Automatic Extension Loading</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_cancel_auto_extension">sqlite3_cancel_auto_extension(X)</a> interface unregisters the
|
|
initialization routine X that was registered using a prior call to
|
|
<a href="#sqlite3_auto_extension">sqlite3_auto_extension(X)</a>. The <a href="#sqlite3_cancel_auto_extension">sqlite3_cancel_auto_extension(X)</a>
|
|
routine returns 1 if initialization routine X was successfully
|
|
unregistered and it returns 0 if X was not on the list of initialization
|
|
routines.
|
|
</p><hr><a name="sqlite3_changes"></a>
|
|
<h2>Count The Number Of Rows Modified</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_changes(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function returns the number of rows modified, inserted or
|
|
deleted by the most recently completed INSERT, UPDATE or DELETE
|
|
statement on the database connection specified by the only parameter.
|
|
Executing any other type of SQL statement does not modify the value
|
|
returned by this function.</p>
|
|
|
|
<p>Only changes made directly by the INSERT, UPDATE or DELETE statement are
|
|
considered - auxiliary changes caused by <a href="lang_createtrigger.html">triggers</a>,
|
|
<a href="foreignkeys.html#fk_actions">foreign key actions</a> or <a href="lang_replace.html">REPLACE</a> constraint resolution are not counted.</p>
|
|
|
|
<p>Changes to a view that are intercepted by
|
|
<a href="lang_createtrigger.html#instead_of_trigger">INSTEAD OF triggers</a> are not counted. The value
|
|
returned by sqlite3_changes() immediately after an INSERT, UPDATE or
|
|
DELETE statement run on a view is always zero. Only changes made to real
|
|
tables are counted.</p>
|
|
|
|
<p>Things are more complicated if the sqlite3_changes() function is
|
|
executed while a trigger program is running. This may happen if the
|
|
program uses the <a href="lang_corefunc.html#changes">changes() SQL function</a>, or if some other callback
|
|
function invokes sqlite3_changes() directly. Essentially:</p>
|
|
|
|
<p><ul>
|
|
<li> Before entering a trigger program the value returned by
|
|
sqlite3_changes() function is saved. After the trigger program
|
|
has finished, the original value is restored.</p>
|
|
|
|
<p><li> Within a trigger program each INSERT, UPDATE and DELETE
|
|
statement sets the value returned by sqlite3_changes()
|
|
upon completion as normal. Of course, this value will not include
|
|
any changes performed by sub-triggers, as the sqlite3_changes()
|
|
value will be saved and restored after each sub-trigger has run.
|
|
</ul></p>
|
|
|
|
<p>This means that if the changes() SQL function (or similar) is used
|
|
by the first INSERT, UPDATE or DELETE statement within a trigger, it
|
|
returns the value as set when the calling statement began executing.
|
|
If it is used by the second or subsequent such statement within a trigger
|
|
program, the value returned reflects the number of rows modified by the
|
|
previous INSERT, UPDATE or DELETE statement within the same trigger.</p>
|
|
|
|
<p>If a separate thread makes changes on the same database connection
|
|
while <a href="#sqlite3_changes">sqlite3_changes()</a> is running then the value returned
|
|
is unpredictable and not meaningful.</p>
|
|
|
|
<p>See also:
|
|
<ul>
|
|
<li> the <a href="#sqlite3_total_changes">sqlite3_total_changes()</a> interface
|
|
<li> the <a href="pragma.html#pragma_count_changes">count_changes pragma</a>
|
|
<li> the <a href="lang_corefunc.html#changes">changes() SQL function</a>
|
|
<li> the <a href="pragma.html#pragma_data_version">data_version pragma</a>
|
|
</ul>
|
|
</p><hr><a name="sqlite3_clear_bindings"></a>
|
|
<h2>Reset All Bindings On A Prepared Statement</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_clear_bindings(sqlite3_stmt*);
|
|
</pre></blockquote>
|
|
<p>
|
|
Contrary to the intuition of many, <a href="#sqlite3_reset">sqlite3_reset()</a> does not reset
|
|
the <a href="#sqlite3_bind_blob">bindings</a> on a <a href="#sqlite3_stmt">prepared statement</a>.
|
|
Use this routine to reset all host parameters to NULL.
|
|
</p><hr><a name="sqlite3_column_count"></a>
|
|
<h2>Number Of Columns In A Result Set</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_column_count(sqlite3_stmt *pStmt);
|
|
</pre></blockquote>
|
|
<p>
|
|
Return the number of columns in the result set returned by the
|
|
<a href="#sqlite3_stmt">prepared statement</a>. If this routine returns 0, that means the
|
|
<a href="#sqlite3_stmt">prepared statement</a> returns no data (for example an <a href="lang_update.html">UPDATE</a>).
|
|
However, just because this routine returns a positive number does not
|
|
mean that one or more rows of data will be returned. A SELECT statement
|
|
will always have a positive sqlite3_column_count() but depending on the
|
|
WHERE clause constraints and the table content, it might return no rows.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_data_count">sqlite3_data_count()</a>
|
|
</p><hr><a name="sqlite3_config"></a>
|
|
<h2>Configuring The SQLite Library</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_config(int, ...);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_config() interface is used to make global configuration
|
|
changes to SQLite in order to tune SQLite to the specific needs of
|
|
the application. The default configuration is recommended for most
|
|
applications and so this routine is usually not necessary. It is
|
|
provided to support rare applications with unusual needs.</p>
|
|
|
|
<p><b>The sqlite3_config() interface is not threadsafe. The application
|
|
must ensure that no other SQLite interfaces are invoked by other
|
|
threads while sqlite3_config() is running.</b></p>
|
|
|
|
<p>The sqlite3_config() interface
|
|
may only be invoked prior to library initialization using
|
|
<a href="#sqlite3_initialize">sqlite3_initialize()</a> or after shutdown by <a href="#sqlite3_initialize">sqlite3_shutdown()</a>.
|
|
If sqlite3_config() is called after <a href="#sqlite3_initialize">sqlite3_initialize()</a> and before
|
|
<a href="#sqlite3_initialize">sqlite3_shutdown()</a> then it will return SQLITE_MISUSE.
|
|
Note, however, that sqlite3_config() can be called as part of the
|
|
implementation of an application-defined <a href="#sqlite3_initialize">sqlite3_os_init()</a>.</p>
|
|
|
|
<p>The first argument to sqlite3_config() is an integer
|
|
<a href="#SQLITE_CONFIG_COVERING_INDEX_SCAN">configuration option</a> that determines
|
|
what property of SQLite is to be configured. Subsequent arguments
|
|
vary depending on the <a href="#SQLITE_CONFIG_COVERING_INDEX_SCAN">configuration option</a>
|
|
in the first argument.</p>
|
|
|
|
<p>When a configuration option is set, sqlite3_config() returns <a href="#SQLITE_ABORT">SQLITE_OK</a>.
|
|
If the option is unknown or SQLite is unable to set the option
|
|
then this routine returns a non-zero <a href="rescode.html">error code</a>.
|
|
</p><hr><a name="sqlite3_context_db_handle"></a>
|
|
<h2>Database Connection For Functions</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_context_db_handle() interface returns a copy of
|
|
the pointer to the <a href="#sqlite3">database connection</a> (the 1st parameter)
|
|
of the <a href="#sqlite3_create_function">sqlite3_create_function()</a>
|
|
and <a href="#sqlite3_create_function">sqlite3_create_function16()</a> routines that originally
|
|
registered the application defined function.
|
|
</p><hr><a name="sqlite3_data_count"></a>
|
|
<h2>Number of columns in a result set</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_data_count(sqlite3_stmt *pStmt);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_data_count(P) interface returns the number of columns in the
|
|
current row of the result set of <a href="#sqlite3_stmt">prepared statement</a> P.
|
|
If prepared statement P does not have results ready to return
|
|
(via calls to the <a href="#sqlite3_column_blob">sqlite3_column()</a> family of
|
|
interfaces) then sqlite3_data_count(P) returns 0.
|
|
The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
|
|
The sqlite3_data_count(P) routine returns 0 if the previous call to
|
|
<a href="#sqlite3_step">sqlite3_step</a>(P) returned <a href="#SQLITE_ABORT">SQLITE_DONE</a>. The sqlite3_data_count(P)
|
|
will return non-zero if previous call to <a href="#sqlite3_step">sqlite3_step</a>(P) returned
|
|
<a href="#SQLITE_ABORT">SQLITE_ROW</a>, except in the case of the <a href="pragma.html#pragma_incremental_vacuum">PRAGMA incremental_vacuum</a>
|
|
where it always returns zero since each step of that multi-step
|
|
pragma returns 0 columns of data.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_column_count">sqlite3_column_count()</a>
|
|
</p><hr><a name="sqlite3_database_file_object"></a>
|
|
<h2>Database File Corresponding To A Journal</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_file *sqlite3_database_file_object(const char*);
|
|
</pre></blockquote>
|
|
<p>
|
|
If X is the name of a rollback or WAL-mode journal file that is
|
|
passed into the xOpen method of <a href="#sqlite3_vfs">sqlite3_vfs</a>, then
|
|
sqlite3_database_file_object(X) returns a pointer to the <a href="#sqlite3_file">sqlite3_file</a>
|
|
object that represents the main database file.</p>
|
|
|
|
<p>This routine is intended for use in custom <a href="vfs.html">VFS</a> implementations
|
|
only. It is not a general-purpose interface.
|
|
The argument sqlite3_file_object(X) must be a filename pointer that
|
|
has been passed into <a href="#sqlite3_vfs">sqlite3_vfs</a>.xOpen method where the
|
|
flags parameter to xOpen contains one of the bits
|
|
<a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_MAIN_JOURNAL</a> or <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_WAL</a>. Any other use
|
|
of this routine results in undefined and probably undesirable
|
|
behavior.
|
|
</p><hr><a name="sqlite3_db_cacheflush"></a>
|
|
<h2>Flush caches to disk mid-transaction</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_db_cacheflush(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
If a write-transaction is open on <a href="#sqlite3">database connection</a> D when the
|
|
<a href="#sqlite3_db_cacheflush">sqlite3_db_cacheflush(D)</a> interface invoked, any dirty
|
|
pages in the pager-cache that are not currently in use are written out
|
|
to disk. A dirty page may be in use if a database cursor created by an
|
|
active SQL statement is reading from it, or if it is page 1 of a database
|
|
file (page 1 is always "in use"). The <a href="#sqlite3_db_cacheflush">sqlite3_db_cacheflush(D)</a>
|
|
interface flushes caches for all schemas - "main", "temp", and
|
|
any <a href="lang_attach.html">attached</a> databases.</p>
|
|
|
|
<p>If this function needs to obtain extra database locks before dirty pages
|
|
can be flushed to disk, it does so. If those locks cannot be obtained
|
|
immediately and there is a busy-handler callback configured, it is invoked
|
|
in the usual manner. If the required lock still cannot be obtained, then
|
|
the database is skipped and an attempt made to flush any dirty pages
|
|
belonging to the next (if any) database. If any databases are skipped
|
|
because locks cannot be obtained, but no other error occurs, this
|
|
function returns SQLITE_BUSY.</p>
|
|
|
|
<p>If any other error occurs while flushing dirty pages to disk (for
|
|
example an IO error or out-of-memory condition), then processing is
|
|
abandoned and an SQLite <a href="rescode.html">error code</a> is returned to the caller immediately.</p>
|
|
|
|
<p>Otherwise, if no error occurs, <a href="#sqlite3_db_cacheflush">sqlite3_db_cacheflush()</a> returns SQLITE_OK.</p>
|
|
|
|
<p>This function does not set the database handle error code or message
|
|
returned by the <a href="#sqlite3_errcode">sqlite3_errcode()</a> and <a href="#sqlite3_errcode">sqlite3_errmsg()</a> functions.
|
|
</p><hr><a name="sqlite3_db_config"></a>
|
|
<h2>Configure database connections</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_db_config(sqlite3*, int op, ...);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_db_config() interface is used to make configuration
|
|
changes to a <a href="#sqlite3">database connection</a>. The interface is similar to
|
|
<a href="#sqlite3_config">sqlite3_config()</a> except that the changes apply to a single
|
|
<a href="#sqlite3">database connection</a> (specified in the first argument).</p>
|
|
|
|
<p>The second argument to sqlite3_db_config(D,V,...) is the
|
|
<a href="#sqlitedbconfiglookaside">configuration verb</a> - an integer code
|
|
that indicates what aspect of the <a href="#sqlite3">database connection</a> is being configured.
|
|
Subsequent arguments vary depending on the configuration verb.</p>
|
|
|
|
<p>Calls to sqlite3_db_config() return SQLITE_OK if and only if
|
|
the call is considered successful.
|
|
</p><hr><a name="sqlite3_db_filename"></a>
|
|
<h2>Return The Filename For A Database Connection</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_db_filename(D,N) interface returns a pointer to the filename
|
|
associated with database N of connection D.
|
|
If there is no attached database N on the database
|
|
connection D, or if database N is a temporary or in-memory database, then
|
|
this function will return either a NULL pointer or an empty string.</p>
|
|
|
|
<p>The string value returned by this routine is owned and managed by
|
|
the database connection. The value will be valid until the database N
|
|
is <a href="lang_detach.html">DETACH</a>-ed or until the database connection closes.</p>
|
|
|
|
<p>The filename returned by this function is the output of the
|
|
xFullPathname method of the <a href="vfs.html">VFS</a>. In other words, the filename
|
|
will be an absolute pathname, even if the filename used
|
|
to open the database originally was a URI or relative pathname.</p>
|
|
|
|
<p>If the filename pointer returned by this routine is not NULL, then it
|
|
can be used as the filename input parameter to these routines:
|
|
<ul>
|
|
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_parameter()</a>
|
|
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_boolean()</a>
|
|
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_int64()</a>
|
|
<li> <a href="#sqlite3_filename_database">sqlite3_filename_database()</a>
|
|
<li> <a href="#sqlite3_filename_database">sqlite3_filename_journal()</a>
|
|
<li> <a href="#sqlite3_filename_database">sqlite3_filename_wal()</a>
|
|
</ul>
|
|
</p><hr><a name="sqlite3_db_handle"></a>
|
|
<h2>Find The Database Handle Of A Prepared Statement</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_db_handle interface returns the <a href="#sqlite3">database connection</a> handle
|
|
to which a <a href="#sqlite3_stmt">prepared statement</a> belongs. The <a href="#sqlite3">database connection</a>
|
|
returned by sqlite3_db_handle is the same <a href="#sqlite3">database connection</a>
|
|
that was the first argument
|
|
to the <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> call (or its variants) that was used to
|
|
create the statement in the first place.
|
|
</p><hr><a name="sqlite3_db_mutex"></a>
|
|
<h2>Retrieve the mutex for a database connection</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
This interface returns a pointer the <a href="#sqlite3_mutex">sqlite3_mutex</a> object that
|
|
serializes access to the <a href="#sqlite3">database connection</a> given in the argument
|
|
when the <a href="threadsafe.html">threading mode</a> is Serialized.
|
|
If the <a href="threadsafe.html">threading mode</a> is Single-thread or Multi-thread then this
|
|
routine returns a NULL pointer.
|
|
</p><hr><a name="sqlite3_db_readonly"></a>
|
|
<h2>Determine if a database is read-only</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_db_readonly(D,N) interface returns 1 if the database N
|
|
of connection D is read-only, 0 if it is read/write, or -1 if N is not
|
|
the name of a database on connection D.
|
|
</p><hr><a name="sqlite3_db_release_memory"></a>
|
|
<h2>Free Memory Used By A Database Connection</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_db_release_memory(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_db_release_memory(D) interface attempts to free as much heap
|
|
memory as possible from database connection D. Unlike the
|
|
<a href="#sqlite3_release_memory">sqlite3_release_memory()</a> interface, this interface is in effect even
|
|
when the <a href="compile.html#enable_memory_management">SQLITE_ENABLE_MEMORY_MANAGEMENT</a> compile-time option is
|
|
omitted.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_release_memory">sqlite3_release_memory()</a>
|
|
</p><hr><a name="sqlite3_db_status"></a>
|
|
<h2>Database Connection Status</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
|
|
</pre></blockquote>
|
|
<p>
|
|
This interface is used to retrieve runtime status information
|
|
about a single <a href="#sqlite3">database connection</a>. The first argument is the
|
|
database connection object to be interrogated. The second argument
|
|
is an integer constant, taken from the set of
|
|
<a href="#SQLITE_DBSTATUS options">SQLITE_DBSTATUS options</a>, that
|
|
determines the parameter to interrogate. The set of
|
|
<a href="#SQLITE_DBSTATUS options">SQLITE_DBSTATUS options</a> is likely
|
|
to grow in future releases of SQLite.</p>
|
|
|
|
<p>The current value of the requested parameter is written into *pCur
|
|
and the highest instantaneous value is written into *pHiwtr. If
|
|
the resetFlg is true, then the highest instantaneous value is
|
|
reset back down to the current value.</p>
|
|
|
|
<p>The sqlite3_db_status() routine returns SQLITE_OK on success and a
|
|
non-zero <a href="rescode.html">error code</a> on failure.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_status">sqlite3_status()</a> and <a href="#sqlite3_stmt_status">sqlite3_stmt_status()</a>.
|
|
</p><hr><a name="sqlite3_declare_vtab"></a>
|
|
<h2>Declare The Schema Of A Virtual Table</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="vtab.html#xcreate">xCreate</a> and <a href="vtab.html#xconnect">xConnect</a> methods of a
|
|
<a href="#sqlite3_module">virtual table module</a> call this interface
|
|
to declare the format (the names and datatypes of the columns) of
|
|
the virtual tables they implement.
|
|
</p><hr><a name="sqlite3_deserialize"></a>
|
|
<h2>Deserialize a database</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_deserialize(
|
|
sqlite3 *db, /* The database connection */
|
|
const char *zSchema, /* Which DB to reopen with the deserialization */
|
|
unsigned char *pData, /* The serialized database content */
|
|
sqlite3_int64 szDb, /* Number bytes in the deserialization */
|
|
sqlite3_int64 szBuf, /* Total size of buffer pData[] */
|
|
unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
|
|
<a href="#sqlite3">database connection</a> D to disconnect from database S and then
|
|
reopen S as an in-memory database based on the serialization contained
|
|
in P. The serialized database P is N bytes in size. M is the size of
|
|
the buffer P, which might be larger than N. If M is larger than N, and
|
|
the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is
|
|
permitted to add content to the in-memory database as long as the total
|
|
size does not exceed M bytes.</p>
|
|
|
|
<p>If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
|
|
invoke sqlite3_free() on the serialization buffer when the database
|
|
connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
|
|
SQLite will try to increase the buffer size using sqlite3_realloc64()
|
|
if writes on the database cause it to grow larger than M bytes.</p>
|
|
|
|
<p>The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
|
|
database is currently in a read transaction or is involved in a backup
|
|
operation.</p>
|
|
|
|
<p>If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
|
|
SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
|
|
<a href="#sqlite3_free">sqlite3_free()</a> is invoked on argument P prior to returning.</p>
|
|
|
|
<p>This interface is only available if SQLite is compiled with the
|
|
<a href="compile.html#enable_deserialize">SQLITE_ENABLE_DESERIALIZE</a> option.
|
|
</p><hr><a name="sqlite3_drop_modules"></a>
|
|
<h2>Remove Unnecessary Virtual Table Implementations</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_drop_modules(
|
|
sqlite3 *db, /* Remove modules from this connection */
|
|
const char **azKeep /* Except, do not remove the ones named here */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_drop_modules(D,L) interface removes all virtual
|
|
table modules from database connection D except those named on list L.
|
|
The L parameter must be either NULL or a pointer to an array of pointers
|
|
to strings where the array is terminated by a single NULL pointer.
|
|
If the L parameter is NULL, then all virtual table modules are removed.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_create_module">sqlite3_create_module()</a>
|
|
</p><hr><a name="sqlite3_enable_load_extension"></a>
|
|
<h2>Enable Or Disable Extension Loading</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
|
|
</pre></blockquote>
|
|
<p>
|
|
So as not to open security holes in older applications that are
|
|
unprepared to deal with <a href="loadext.html">extension loading</a>, and as a means of disabling
|
|
<a href="loadext.html">extension loading</a> while evaluating user-entered SQL, the following API
|
|
is provided to turn the <a href="#sqlite3_load_extension">sqlite3_load_extension()</a> mechanism on and off.</p>
|
|
|
|
<p>Extension loading is off by default.
|
|
Call the sqlite3_enable_load_extension() routine with onoff==1
|
|
to turn extension loading on and call it with onoff==0 to turn
|
|
it back off again.</p>
|
|
|
|
<p>This interface enables or disables both the C-API
|
|
<a href="#sqlite3_load_extension">sqlite3_load_extension()</a> and the SQL function <a href="lang_corefunc.html#load_extension">load_extension()</a>.
|
|
Use <a href="#sqlite3_db_config">sqlite3_db_config</a>(db,<a href="#sqlitedbconfigenableloadextension">SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a>,..)
|
|
to enable or disable only the C-API.</p>
|
|
|
|
<p><b>Security warning:</b> It is recommended that extension loading
|
|
be enabled using the <a href="#sqlitedbconfigenableloadextension">SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a> method
|
|
rather than this interface, so the <a href="lang_corefunc.html#load_extension">load_extension()</a> SQL function
|
|
remains disabled. This will prevent SQL injections from giving attackers
|
|
access to extension loading capabilities.
|
|
</p><hr><a name="sqlite3_enable_shared_cache"></a>
|
|
<h2>Enable Or Disable Shared Pager Cache</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_enable_shared_cache(int);
|
|
</pre></blockquote>
|
|
<p>
|
|
This routine enables or disables the sharing of the database cache
|
|
and schema data structures between <a href="#sqlite3">connections</a>
|
|
to the same database. Sharing is enabled if the argument is true
|
|
and disabled if the argument is false.</p>
|
|
|
|
<p>Cache sharing is enabled and disabled for an entire process.
|
|
This is a change as of SQLite <a href="releaselog/3_5_0.html">version 3.5.0</a> (2007-09-04).
|
|
In prior versions of SQLite,
|
|
sharing was enabled or disabled for each thread separately.</p>
|
|
|
|
<p>The cache sharing mode set by this interface effects all subsequent
|
|
calls to <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open_v2()</a>, and <a href="#sqlite3_open">sqlite3_open16()</a>.
|
|
Existing database connections continue to use the sharing mode
|
|
that was in effect at the time they were opened.</p>
|
|
|
|
<p>This routine returns <a href="#SQLITE_ABORT">SQLITE_OK</a> if shared cache was enabled or disabled
|
|
successfully. An <a href="rescode.html">error code</a> is returned otherwise.</p>
|
|
|
|
<p>Shared cache is disabled by default. It is recommended that it stay
|
|
that way. In other words, do not use this routine. This interface
|
|
continues to be provided for historical compatibility, but its use is
|
|
discouraged. Any use of shared cache is discouraged. If shared cache
|
|
must be used, it is recommended that shared cache only be enabled for
|
|
individual database connections using the <a href="#sqlite3_open">sqlite3_open_v2()</a> interface
|
|
with the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SHAREDCACHE</a> flag.</p>
|
|
|
|
<p>Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
|
|
and will always return SQLITE_MISUSE. On those systems,
|
|
shared cache mode should be enabled per-database connection via
|
|
<a href="#sqlite3_open">sqlite3_open_v2()</a> with <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SHAREDCACHE</a>.</p>
|
|
|
|
<p>This interface is threadsafe on processors where writing a
|
|
32-bit integer is atomic.</p>
|
|
|
|
<p>See Also: <a href="sharedcache.html">SQLite Shared-Cache Mode</a>
|
|
</p><hr><a name="sqlite3_exec"></a>
|
|
<h2>One-Step Query Execution Interface</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_exec(
|
|
sqlite3*, /* An open database */
|
|
const char *sql, /* SQL to be evaluated */
|
|
int (*callback)(void*,int,char**,char**), /* Callback function */
|
|
void *, /* 1st argument to callback */
|
|
char **errmsg /* Error msg written here */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_exec() interface is a convenience wrapper around
|
|
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_step">sqlite3_step()</a>, and <a href="#sqlite3_finalize">sqlite3_finalize()</a>,
|
|
that allows an application to run multiple statements of SQL
|
|
without having to use a lot of C code.</p>
|
|
|
|
<p>The sqlite3_exec() interface runs zero or more UTF-8 encoded,
|
|
semicolon-separate SQL statements passed into its 2nd argument,
|
|
in the context of the <a href="#sqlite3">database connection</a> passed in as its 1st
|
|
argument. If the callback function of the 3rd argument to
|
|
sqlite3_exec() is not NULL, then it is invoked for each result row
|
|
coming out of the evaluated SQL statements. The 4th argument to
|
|
sqlite3_exec() is relayed through to the 1st argument of each
|
|
callback invocation. If the callback pointer to sqlite3_exec()
|
|
is NULL, then no callback is ever invoked and result rows are
|
|
ignored.</p>
|
|
|
|
<p>If an error occurs while evaluating the SQL statements passed into
|
|
sqlite3_exec(), then execution of the current statement stops and
|
|
subsequent statements are skipped. If the 5th parameter to sqlite3_exec()
|
|
is not NULL then any error message is written into memory obtained
|
|
from <a href="#sqlite3_free">sqlite3_malloc()</a> and passed back through the 5th parameter.
|
|
To avoid memory leaks, the application should invoke <a href="#sqlite3_free">sqlite3_free()</a>
|
|
on error message strings returned through the 5th parameter of
|
|
sqlite3_exec() after the error message string is no longer needed.
|
|
If the 5th parameter to sqlite3_exec() is not NULL and no errors
|
|
occur, then sqlite3_exec() sets the pointer in its 5th parameter to
|
|
NULL before returning.</p>
|
|
|
|
<p>If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
|
|
routine returns SQLITE_ABORT without invoking the callback again and
|
|
without running any subsequent SQL statements.</p>
|
|
|
|
<p>The 2nd argument to the sqlite3_exec() callback function is the
|
|
number of columns in the result. The 3rd argument to the sqlite3_exec()
|
|
callback is an array of pointers to strings obtained as if from
|
|
<a href="#sqlite3_column_blob">sqlite3_column_text()</a>, one for each column. If an element of a
|
|
result row is NULL then the corresponding string pointer for the
|
|
sqlite3_exec() callback is a NULL pointer. The 4th argument to the
|
|
sqlite3_exec() callback is an array of pointers to strings where each
|
|
entry represents the name of corresponding result column as obtained
|
|
from <a href="#sqlite3_column_name">sqlite3_column_name()</a>.</p>
|
|
|
|
<p>If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
|
|
to an empty string, or a pointer that contains only whitespace and/or
|
|
SQL comments, then no SQL statements are evaluated and the database
|
|
is not changed.</p>
|
|
|
|
<p>Restrictions:</p>
|
|
|
|
<p><ul>
|
|
<li> The application must ensure that the 1st parameter to sqlite3_exec()
|
|
is a valid and open <a href="#sqlite3">database connection</a>.
|
|
<li> The application must not close the <a href="#sqlite3">database connection</a> specified by
|
|
the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
|
|
<li> The application must not modify the SQL statement text passed into
|
|
the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
|
|
</ul>
|
|
</p><hr><a name="sqlite3_extended_result_codes"></a>
|
|
<h2>Enable Or Disable Extended Result Codes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_extended_result_codes(sqlite3*, int onoff);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_extended_result_codes() routine enables or disables the
|
|
<a href="rescode.html#extrc">extended result codes</a> feature of SQLite. The extended result
|
|
codes are disabled by default for historical compatibility.
|
|
</p><hr><a name="sqlite3_finalize"></a>
|
|
<h2>Destroy A Prepared Statement Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_finalize(sqlite3_stmt *pStmt);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_finalize() function is called to delete a <a href="#sqlite3_stmt">prepared statement</a>.
|
|
If the most recent evaluation of the statement encountered no errors
|
|
or if the statement is never been evaluated, then sqlite3_finalize() returns
|
|
SQLITE_OK. If the most recent evaluation of statement S failed, then
|
|
sqlite3_finalize(S) returns the appropriate <a href="rescode.html">error code</a> or
|
|
<a href="rescode.html#extrc">extended error code</a>.</p>
|
|
|
|
<p>The sqlite3_finalize(S) routine can be called at any point during
|
|
the life cycle of <a href="#sqlite3_stmt">prepared statement</a> S:
|
|
before statement S is ever evaluated, after
|
|
one or more calls to <a href="#sqlite3_reset">sqlite3_reset()</a>, or after any call
|
|
to <a href="#sqlite3_step">sqlite3_step()</a> regardless of whether or not the statement has
|
|
completed execution.</p>
|
|
|
|
<p>Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.</p>
|
|
|
|
<p>The application must finalize every <a href="#sqlite3_stmt">prepared statement</a> in order to avoid
|
|
resource leaks. It is a grievous error for the application to try to use
|
|
a prepared statement after it has been finalized. Any use of a prepared
|
|
statement after it has been finalized can result in undefined and
|
|
undesirable behavior such as segfaults and heap corruption.
|
|
</p><hr><a name="sqlite3_interrupt"></a>
|
|
<h2>Interrupt A Long-Running Query</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_interrupt(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function causes any pending database operation to abort and
|
|
return at its earliest opportunity. This routine is typically
|
|
called in response to a user action such as pressing "Cancel"
|
|
or Ctrl-C where the user wants a long query operation to halt
|
|
immediately.</p>
|
|
|
|
<p>It is safe to call this routine from a thread different from the
|
|
thread that is currently running the database operation. But it
|
|
is not safe to call this routine with a <a href="#sqlite3">database connection</a> that
|
|
is closed or might close before sqlite3_interrupt() returns.</p>
|
|
|
|
<p>If an SQL operation is very nearly finished at the time when
|
|
sqlite3_interrupt() is called, then it might not have an opportunity
|
|
to be interrupted and might continue to completion.</p>
|
|
|
|
<p>An SQL operation that is interrupted will return <a href="#SQLITE_ABORT">SQLITE_INTERRUPT</a>.
|
|
If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
|
|
that is inside an explicit transaction, then the entire transaction
|
|
will be rolled back automatically.</p>
|
|
|
|
<p>The sqlite3_interrupt(D) call is in effect until all currently running
|
|
SQL statements on <a href="#sqlite3">database connection</a> D complete. Any new SQL statements
|
|
that are started after the sqlite3_interrupt() call and before the
|
|
running statement count reaches zero are interrupted as if they had been
|
|
running prior to the sqlite3_interrupt() call. New SQL statements
|
|
that are started after the running statement count reaches zero are
|
|
not effected by the sqlite3_interrupt().
|
|
A call to sqlite3_interrupt(D) that occurs when there are no running
|
|
SQL statements is a no-op and has no effect on SQL statements
|
|
that are started after the sqlite3_interrupt() call returns.
|
|
</p><hr><a name="sqlite3_last_insert_rowid"></a>
|
|
<h2>Last Insert Rowid</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
Each entry in most SQLite tables (except for <a href="withoutrowid.html">WITHOUT ROWID</a> tables)
|
|
has a unique 64-bit signed
|
|
integer key called the <a href="lang_createtable.html#rowid">"rowid"</a>. The rowid is always available
|
|
as an undeclared column named ROWID, OID, or _ROWID_ as long as those
|
|
names are not also used by explicitly declared columns. If
|
|
the table has a column of type <a href="lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> then that column
|
|
is another alias for the rowid.</p>
|
|
|
|
<p>The sqlite3_last_insert_rowid(D) interface usually returns the <a href="lang_createtable.html#rowid">rowid</a> of
|
|
the most recent successful <a href="lang_insert.html">INSERT</a> into a rowid table or <a href="vtab.html">virtual table</a>
|
|
on database connection D. Inserts into <a href="withoutrowid.html">WITHOUT ROWID</a> tables are not
|
|
recorded. If no successful <a href="lang_insert.html">INSERT</a>s into rowid tables have ever occurred
|
|
on the database connection D, then sqlite3_last_insert_rowid(D) returns
|
|
zero.</p>
|
|
|
|
<p>As well as being set automatically as rows are inserted into database
|
|
tables, the value returned by this function may be set explicitly by
|
|
<a href="#sqlite3_set_last_insert_rowid">sqlite3_set_last_insert_rowid()</a></p>
|
|
|
|
<p>Some virtual table implementations may INSERT rows into rowid tables as
|
|
part of committing a transaction (e.g. to flush data accumulated in memory
|
|
to disk). In this case subsequent calls to this function return the rowid
|
|
associated with these internal INSERT operations, which leads to
|
|
unintuitive results. Virtual table implementations that do write to rowid
|
|
tables in this way can avoid this problem by restoring the original
|
|
rowid value using <a href="#sqlite3_set_last_insert_rowid">sqlite3_set_last_insert_rowid()</a> before returning
|
|
control to the user.</p>
|
|
|
|
<p>If an <a href="lang_insert.html">INSERT</a> occurs within a trigger then this routine will
|
|
return the <a href="lang_createtable.html#rowid">rowid</a> of the inserted row as long as the trigger is
|
|
running. Once the trigger program ends, the value returned
|
|
by this routine reverts to what it was before the trigger was fired.</p>
|
|
|
|
<p>An <a href="lang_insert.html">INSERT</a> that fails due to a constraint violation is not a
|
|
successful <a href="lang_insert.html">INSERT</a> and does not change the value returned by this
|
|
routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
|
|
and INSERT OR ABORT make no changes to the return value of this
|
|
routine when their insertion fails. When INSERT OR REPLACE
|
|
encounters a constraint violation, it does not fail. The
|
|
INSERT continues to completion after deleting rows that caused
|
|
the constraint problem so INSERT OR REPLACE will always change
|
|
the return value of this interface.</p>
|
|
|
|
<p>For the purposes of this routine, an <a href="lang_insert.html">INSERT</a> is considered to
|
|
be successful even if it is subsequently rolled back.</p>
|
|
|
|
<p>This function is accessible to SQL statements via the
|
|
<a href="lang_corefunc.html#last_insert_rowid">last_insert_rowid() SQL function</a>.</p>
|
|
|
|
<p>If a separate thread performs a new <a href="lang_insert.html">INSERT</a> on the same
|
|
database connection while the <a href="#sqlite3_last_insert_rowid">sqlite3_last_insert_rowid()</a>
|
|
function is running and thus changes the last insert <a href="lang_createtable.html#rowid">rowid</a>,
|
|
then the value returned by <a href="#sqlite3_last_insert_rowid">sqlite3_last_insert_rowid()</a> is
|
|
unpredictable and might not equal either the old or the new
|
|
last insert <a href="lang_createtable.html#rowid">rowid</a>.
|
|
</p><hr><a name="sqlite3_limit"></a>
|
|
<h2>Run-time Limits</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_limit(sqlite3*, int id, int newVal);
|
|
</pre></blockquote>
|
|
<p>
|
|
This interface allows the size of various constructs to be limited
|
|
on a connection by connection basis. The first parameter is the
|
|
<a href="#sqlite3">database connection</a> whose limit is to be set or queried. The
|
|
second parameter is one of the <a href="#SQLITE_LIMIT_ATTACHED">limit categories</a> that define a
|
|
class of constructs to be size limited. The third parameter is the
|
|
new limit for that construct.</p>
|
|
|
|
<p>If the new limit is a negative number, the limit is unchanged.
|
|
For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
|
|
<a href="limits.html">hard upper bound</a>
|
|
set at compile-time by a C preprocessor macro called
|
|
<a href="limits.html">SQLITE_MAX_<i>NAME</i></a>.
|
|
(The "_LIMIT_" in the name is changed to "_MAX_".)
|
|
Attempts to increase a limit above its hard upper bound are
|
|
silently truncated to the hard upper bound.</p>
|
|
|
|
<p>Regardless of whether or not the limit was changed, the
|
|
<a href="#sqlite3_limit">sqlite3_limit()</a> interface returns the prior value of the limit.
|
|
Hence, to find the current value of a limit without changing it,
|
|
simply invoke this interface with the third parameter set to -1.</p>
|
|
|
|
<p>Run-time limits are intended for use in applications that manage
|
|
both their own internal database and also databases that are controlled
|
|
by untrusted external sources. An example application might be a
|
|
web browser that has its own databases for storing history and
|
|
separate databases controlled by JavaScript applications downloaded
|
|
off the Internet. The internal databases can be given the
|
|
large, default limits. Databases managed by external sources can
|
|
be given much smaller limits designed to prevent a denial of service
|
|
attack. Developers might also want to use the <a href="#sqlite3_set_authorizer">sqlite3_set_authorizer()</a>
|
|
interface to further control untrusted SQL. The size of the database
|
|
created by an untrusted script can be contained using the
|
|
<a href="pragma.html#pragma_max_page_count">max_page_count</a> <a href="pragma.html#syntax">PRAGMA</a>.</p>
|
|
|
|
<p>New run-time limit categories may be added in future releases.
|
|
</p><hr><a name="sqlite3_load_extension"></a>
|
|
<h2>Load An Extension</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_load_extension(
|
|
sqlite3 *db, /* Load the extension into this database connection */
|
|
const char *zFile, /* Name of the shared library containing extension */
|
|
const char *zProc, /* Entry point. Derived from zFile if 0 */
|
|
char **pzErrMsg /* Put error message here if not 0 */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
This interface loads an SQLite extension library from the named file.</p>
|
|
|
|
<p>The sqlite3_load_extension() interface attempts to load an
|
|
<a href="loadext.html">SQLite extension</a> library contained in the file zFile. If
|
|
the file cannot be loaded directly, attempts are made to load
|
|
with various operating-system specific extensions added.
|
|
So for example, if "samplelib" cannot be loaded, then names like
|
|
"samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
|
|
be tried also.</p>
|
|
|
|
<p>The entry point is zProc.
|
|
zProc may be 0, in which case SQLite will try to come up with an
|
|
entry point name on its own. It first tries "sqlite3_extension_init".
|
|
If that does not work, it constructs a name "sqlite3_X_init" where the
|
|
X is consists of the lower-case equivalent of all ASCII alphabetic
|
|
characters in the filename from the last "/" to the first following
|
|
"." and omitting any initial "lib".
|
|
The sqlite3_load_extension() interface returns
|
|
<a href="#SQLITE_ABORT">SQLITE_OK</a> on success and <a href="#SQLITE_ABORT">SQLITE_ERROR</a> if something goes wrong.
|
|
If an error occurs and pzErrMsg is not 0, then the
|
|
<a href="#sqlite3_load_extension">sqlite3_load_extension()</a> interface shall attempt to
|
|
fill *pzErrMsg with error message text stored in memory
|
|
obtained from <a href="#sqlite3_free">sqlite3_malloc()</a>. The calling function
|
|
should free this memory by calling <a href="#sqlite3_free">sqlite3_free()</a>.</p>
|
|
|
|
<p>Extension loading must be enabled using
|
|
<a href="#sqlite3_enable_load_extension">sqlite3_enable_load_extension()</a> or
|
|
<a href="#sqlite3_db_config">sqlite3_db_config</a>(db,<a href="#sqlitedbconfigenableloadextension">SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a>,1,NULL)
|
|
prior to calling this API,
|
|
otherwise an error will be returned.</p>
|
|
|
|
<p><b>Security warning:</b> It is recommended that the
|
|
<a href="#sqlitedbconfigenableloadextension">SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</a> method be used to enable only this
|
|
interface. The use of the <a href="#sqlite3_enable_load_extension">sqlite3_enable_load_extension()</a> interface
|
|
should be avoided. This will keep the SQL function <a href="lang_corefunc.html#load_extension">load_extension()</a>
|
|
disabled and prevent SQL injections from giving attackers
|
|
access to extension loading capabilities.</p>
|
|
|
|
<p>See also the <a href="lang_corefunc.html#load_extension">load_extension() SQL function</a>.
|
|
</p><hr><a name="sqlite3_log"></a>
|
|
<h2>Error Logging Interface</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_log(int iErrCode, const char *zFormat, ...);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_log">sqlite3_log()</a> interface writes a message into the <a href="errlog.html">error log</a>
|
|
established by the <a href="#sqliteconfiglog">SQLITE_CONFIG_LOG</a> option to <a href="#sqlite3_config">sqlite3_config()</a>.
|
|
If logging is enabled, the zFormat string and subsequent arguments are
|
|
used with <a href="#sqlite3_mprintf">sqlite3_snprintf()</a> to generate the final output string.</p>
|
|
|
|
<p>The sqlite3_log() interface is intended for use by extensions such as
|
|
virtual tables, collating functions, and SQL functions. While there is
|
|
nothing to prevent an application from calling sqlite3_log(), doing so
|
|
is considered bad form.</p>
|
|
|
|
<p>The zFormat string must not be NULL.</p>
|
|
|
|
<p>To avoid deadlocks and other threading problems, the sqlite3_log() routine
|
|
will not use dynamically allocated memory. The log message is stored in
|
|
a fixed-length buffer on the stack. If the log message is longer than
|
|
a few hundred characters, it will be truncated to the length of the
|
|
buffer.
|
|
</p><hr><a name="sqlite3_next_stmt"></a>
|
|
<h2>Find the next prepared statement</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
|
|
</pre></blockquote>
|
|
<p>
|
|
This interface returns a pointer to the next <a href="#sqlite3_stmt">prepared statement</a> after
|
|
pStmt associated with the <a href="#sqlite3">database connection</a> pDb. If pStmt is NULL
|
|
then this interface returns a pointer to the first prepared statement
|
|
associated with the database connection pDb. If no prepared statement
|
|
satisfies the conditions of this routine, it returns NULL.</p>
|
|
|
|
<p>The <a href="#sqlite3">database connection</a> pointer D in a call to
|
|
<a href="#sqlite3_next_stmt">sqlite3_next_stmt(D,S)</a> must refer to an open database
|
|
connection and in particular must not be a NULL pointer.
|
|
</p><hr><a name="sqlite3_overload_function"></a>
|
|
<h2>Overload A Function For A Virtual Table</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
|
|
</pre></blockquote>
|
|
<p>
|
|
Virtual tables can provide alternative implementations of functions
|
|
using the <a href="vtab.html#xfindfunction">xFindFunction</a> method of the <a href="#sqlite3_module">virtual table module</a>.
|
|
But global versions of those functions
|
|
must exist in order to be overloaded.</p>
|
|
|
|
<p>This API makes sure a global version of a function with a particular
|
|
name and number of parameters exists. If no such function exists
|
|
before this API is called, a new function is created. The implementation
|
|
of the new function always causes an exception to be thrown. So
|
|
the new function is not good for anything by itself. Its only
|
|
purpose is to be a placeholder function that can be overloaded
|
|
by a <a href="vtab.html">virtual table</a>.
|
|
</p><hr><a name="sqlite3_progress_handler"></a>
|
|
<h2>Query Progress Callbacks</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_progress_handler(D,N,X,P) interface causes the callback
|
|
function X to be invoked periodically during long running calls to
|
|
<a href="#sqlite3_exec">sqlite3_exec()</a>, <a href="#sqlite3_step">sqlite3_step()</a> and <a href="#sqlite3_free_table">sqlite3_get_table()</a> for
|
|
database connection D. An example use for this
|
|
interface is to keep a GUI updated during a large query.</p>
|
|
|
|
<p>The parameter P is passed through as the only parameter to the
|
|
callback function X. The parameter N is the approximate number of
|
|
<a href="opcode.html">virtual machine instructions</a> that are evaluated between successive
|
|
invocations of the callback X. If N is less than one then the progress
|
|
handler is disabled.</p>
|
|
|
|
<p>Only a single progress handler may be defined at one time per
|
|
<a href="#sqlite3">database connection</a>; setting a new progress handler cancels the
|
|
old one. Setting parameter X to NULL disables the progress handler.
|
|
The progress handler is also disabled by setting N to a value less
|
|
than 1.</p>
|
|
|
|
<p>If the progress callback returns non-zero, the operation is
|
|
interrupted. This feature can be used to implement a
|
|
"Cancel" button on a GUI progress dialog box.</p>
|
|
|
|
<p>The progress handler callback must not do anything that will modify
|
|
the database connection that invoked the progress handler.
|
|
Note that <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and <a href="#sqlite3_step">sqlite3_step()</a> both modify their
|
|
database connections for the meaning of "modify" in this paragraph.</p>
|
|
|
|
<p></p><hr><a name="sqlite3_randomness"></a>
|
|
<h2>Pseudo-Random Number Generator</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_randomness(int N, void *P);
|
|
</pre></blockquote>
|
|
<p>
|
|
SQLite contains a high-quality pseudo-random number generator (PRNG) used to
|
|
select random <a href="lang_createtable.html#rowid">ROWIDs</a> when inserting new records into a table that
|
|
already uses the largest possible <a href="lang_createtable.html#rowid">ROWID</a>. The PRNG is also used for
|
|
the built-in random() and randomblob() SQL functions. This interface allows
|
|
applications to access the same PRNG for other purposes.</p>
|
|
|
|
<p>A call to this routine stores N bytes of randomness into buffer P.
|
|
The P parameter can be a NULL pointer.</p>
|
|
|
|
<p>If this routine has not been previously called or if the previous
|
|
call had N less than one or a NULL pointer for P, then the PRNG is
|
|
seeded using randomness obtained from the xRandomness method of
|
|
the default <a href="#sqlite3_vfs">sqlite3_vfs</a> object.
|
|
If the previous call to this routine had an N of 1 or more and a
|
|
non-NULL P then the pseudo-randomness is generated
|
|
internally and without recourse to the <a href="#sqlite3_vfs">sqlite3_vfs</a> xRandomness
|
|
method.
|
|
</p><hr><a name="sqlite3_release_memory"></a>
|
|
<h2>Attempt To Free Heap Memory</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_release_memory(int);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_release_memory() interface attempts to free N bytes
|
|
of heap memory by deallocating non-essential memory allocations
|
|
held by the database library. Memory used to cache database
|
|
pages to improve performance is an example of non-essential memory.
|
|
sqlite3_release_memory() returns the number of bytes actually freed,
|
|
which might be more or less than the amount requested.
|
|
The sqlite3_release_memory() routine is a no-op returning zero
|
|
if SQLite is not compiled with <a href="compile.html#enable_memory_management">SQLITE_ENABLE_MEMORY_MANAGEMENT</a>.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_db_release_memory">sqlite3_db_release_memory()</a>
|
|
</p><hr><a name="sqlite3_reset"></a>
|
|
<h2>Reset A Prepared Statement Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_reset(sqlite3_stmt *pStmt);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_reset() function is called to reset a <a href="#sqlite3_stmt">prepared statement</a>
|
|
object back to its initial state, ready to be re-executed.
|
|
Any SQL statement variables that had values bound to them using
|
|
the <a href="#sqlite3_bind_blob">sqlite3_bind_*() API</a> retain their values.
|
|
Use <a href="#sqlite3_clear_bindings">sqlite3_clear_bindings()</a> to reset the bindings.</p>
|
|
|
|
<p>The <a href="#sqlite3_reset">sqlite3_reset(S)</a> interface resets the <a href="#sqlite3_stmt">prepared statement</a> S
|
|
back to the beginning of its program.</p>
|
|
|
|
<p>If the most recent call to <a href="#sqlite3_step">sqlite3_step(S)</a> for the
|
|
<a href="#sqlite3_stmt">prepared statement</a> S returned <a href="#SQLITE_ABORT">SQLITE_ROW</a> or <a href="#SQLITE_ABORT">SQLITE_DONE</a>,
|
|
or if <a href="#sqlite3_step">sqlite3_step(S)</a> has never before been called on S,
|
|
then <a href="#sqlite3_reset">sqlite3_reset(S)</a> returns <a href="#SQLITE_ABORT">SQLITE_OK</a>.</p>
|
|
|
|
<p>If the most recent call to <a href="#sqlite3_step">sqlite3_step(S)</a> for the
|
|
<a href="#sqlite3_stmt">prepared statement</a> S indicated an error, then
|
|
<a href="#sqlite3_reset">sqlite3_reset(S)</a> returns an appropriate <a href="rescode.html">error code</a>.</p>
|
|
|
|
<p>The <a href="#sqlite3_reset">sqlite3_reset(S)</a> interface does not change the values
|
|
of any <a href="#sqlite3_bind_blob">bindings</a> on the <a href="#sqlite3_stmt">prepared statement</a> S.
|
|
</p><hr><a name="sqlite3_reset_auto_extension"></a>
|
|
<h2>Reset Automatic Extension Loading</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_reset_auto_extension(void);
|
|
</pre></blockquote>
|
|
<p>
|
|
This interface disables all automatic extensions previously
|
|
registered using <a href="#sqlite3_auto_extension">sqlite3_auto_extension()</a>.
|
|
</p><hr><a name="sqlite3_result_subtype"></a>
|
|
<h2>Setting The Subtype Of An SQL Function</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_result_subtype(sqlite3_context*,unsigned int);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_result_subtype(C,T) function causes the subtype of
|
|
the result from the <a href="appfunc.html">application-defined SQL function</a> with
|
|
<a href="#sqlite3_context">sqlite3_context</a> C to be the value T. Only the lower 8 bits
|
|
of the subtype T are preserved in current versions of SQLite;
|
|
higher order bits are discarded.
|
|
The number of subtype bytes preserved by SQLite might increase
|
|
in future releases of SQLite.
|
|
</p><hr><a name="sqlite3_serialize"></a>
|
|
<h2>Serialize a database</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
unsigned char *sqlite3_serialize(
|
|
sqlite3 *db, /* The database connection */
|
|
const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */
|
|
sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
|
|
unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory
|
|
that is a serialization of the S database on <a href="#sqlite3">database connection</a> D.
|
|
If P is not a NULL pointer, then the size of the database in bytes
|
|
is written into *P.</p>
|
|
|
|
<p>For an ordinary on-disk database file, the serialization is just a
|
|
copy of the disk file. For an in-memory database or a "TEMP" database,
|
|
the serialization is the same sequence of bytes which would be written
|
|
to disk if that database where backed up to disk.</p>
|
|
|
|
<p>The usual case is that sqlite3_serialize() copies the serialization of
|
|
the database into memory obtained from <a href="#sqlite3_free">sqlite3_malloc64()</a> and returns
|
|
a pointer to that memory. The caller is responsible for freeing the
|
|
returned value to avoid a memory leak. However, if the F argument
|
|
contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
|
|
are made, and the sqlite3_serialize() function will return a pointer
|
|
to the contiguous memory representation of the database that SQLite
|
|
is currently using for that database, or NULL if the no such contiguous
|
|
memory representation of the database exists. A contiguous memory
|
|
representation of the database will usually only exist if there has
|
|
been a prior call to <a href="#sqlite3_deserialize">sqlite3_deserialize(D,S,...)</a> with the same
|
|
values of D and S.
|
|
The size of the database is written into *P even if the
|
|
SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
|
|
of the database exists.</p>
|
|
|
|
<p>A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
|
|
SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
|
|
allocation error occurs.</p>
|
|
|
|
<p>This interface is only available if SQLite is compiled with the
|
|
<a href="compile.html#enable_deserialize">SQLITE_ENABLE_DESERIALIZE</a> option.
|
|
</p><hr><a name="sqlite3_set_last_insert_rowid"></a>
|
|
<h2>Set the Last Insert Rowid value.</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_set_last_insert_rowid(D, R) method allows the application to
|
|
set the value returned by calling sqlite3_last_insert_rowid(D) to R
|
|
without inserting a row into the database.
|
|
</p><hr><a name="sqlite3_sleep"></a>
|
|
<h2>Suspend Execution For A Short Time</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_sleep(int);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_sleep() function causes the current thread to suspend execution
|
|
for at least a number of milliseconds specified in its parameter.</p>
|
|
|
|
<p>If the operating system does not support sleep requests with
|
|
millisecond time resolution, then the time will be rounded up to
|
|
the nearest second. The number of milliseconds of sleep actually
|
|
requested from the operating system is returned.</p>
|
|
|
|
<p>SQLite implements this interface by calling the xSleep()
|
|
method of the default <a href="#sqlite3_vfs">sqlite3_vfs</a> object. If the xSleep() method
|
|
of the default VFS is not implemented correctly, or not implemented at
|
|
all, then the behavior of sqlite3_sleep() may deviate from the description
|
|
in the previous paragraphs.
|
|
</p><hr><a name="sqlite3_snapshot_cmp"></a>
|
|
<h2>Compare the ages of two snapshot handles.</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_snapshot_cmp(
|
|
sqlite3_snapshot *p1,
|
|
sqlite3_snapshot *p2
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
|
|
of two valid snapshot handles.</p>
|
|
|
|
<p>If the two snapshot handles are not associated with the same database
|
|
file, the result of the comparison is undefined.</p>
|
|
|
|
<p>Additionally, the result of the comparison is only valid if both of the
|
|
snapshot handles were obtained by calling sqlite3_snapshot_get() since the
|
|
last time the wal file was deleted. The wal file is deleted when the
|
|
database is changed back to rollback mode or when the number of database
|
|
clients drops to zero. If either snapshot handle was obtained before the
|
|
wal file was last deleted, the value returned by this function
|
|
is undefined.</p>
|
|
|
|
<p>Otherwise, this API returns a negative value if P1 refers to an older
|
|
snapshot than P2, zero if the two handles refer to the same database
|
|
snapshot, and a positive value if P1 is a newer snapshot than P2.</p>
|
|
|
|
<p>This interface is only available if SQLite is compiled with the
|
|
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> option.
|
|
</p><hr><a name="sqlite3_snapshot_free"></a>
|
|
<h2>Destroy a snapshot</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_snapshot_free(sqlite3_snapshot*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_snapshot_free">sqlite3_snapshot_free(P)</a> interface destroys <a href="#sqlite3_snapshot">sqlite3_snapshot</a> P.
|
|
The application must eventually free every <a href="#sqlite3_snapshot">sqlite3_snapshot</a> object
|
|
using this routine to avoid a memory leak.</p>
|
|
|
|
<p>The <a href="#sqlite3_snapshot_free">sqlite3_snapshot_free()</a> interface is only available when the
|
|
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> compile-time option is used.
|
|
</p><hr><a name="sqlite3_snapshot_get"></a>
|
|
<h2>Record A Database Snapshot</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_snapshot_get(
|
|
sqlite3 *db,
|
|
const char *zSchema,
|
|
sqlite3_snapshot **ppSnapshot
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_snapshot_get">sqlite3_snapshot_get(D,S,P)</a> interface attempts to make a
|
|
new <a href="#sqlite3_snapshot">sqlite3_snapshot</a> object that records the current state of
|
|
schema S in database connection D. On success, the
|
|
<a href="#sqlite3_snapshot_get">sqlite3_snapshot_get(D,S,P)</a> interface writes a pointer to the newly
|
|
created <a href="#sqlite3_snapshot">sqlite3_snapshot</a> object into *P and returns SQLITE_OK.
|
|
If there is not already a read-transaction open on schema S when
|
|
this function is called, one is opened automatically.</p>
|
|
|
|
<p>The following must be true for this function to succeed. If any of
|
|
the following statements are false when sqlite3_snapshot_get() is
|
|
called, SQLITE_ERROR is returned. The final value of *P is undefined
|
|
in this case.</p>
|
|
|
|
<p><ul>
|
|
<li> The database handle must not be in <a href="#sqlite3_get_autocommit">autocommit mode</a>.</p>
|
|
|
|
<p><li> Schema S of <a href="#sqlite3">database connection</a> D must be a <a href="wal.html">WAL mode</a> database.</p>
|
|
|
|
<p><li> There must not be a write transaction open on schema S of database
|
|
connection D.</p>
|
|
|
|
<p><li> One or more transactions must have been written to the current wal
|
|
file since it was created on disk (by any connection). This means
|
|
that a snapshot cannot be taken on a wal mode database with no wal
|
|
file immediately after it is first opened. At least one transaction
|
|
must be written to it first.
|
|
</ul></p>
|
|
|
|
<p>This function may also return SQLITE_NOMEM. If it is called with the
|
|
database handle in autocommit mode but fails for some other reason,
|
|
whether or not a read transaction is opened on schema S is undefined.</p>
|
|
|
|
<p>The <a href="#sqlite3_snapshot">sqlite3_snapshot</a> object returned from a successful call to
|
|
<a href="#sqlite3_snapshot_get">sqlite3_snapshot_get()</a> must be freed using <a href="#sqlite3_snapshot_free">sqlite3_snapshot_free()</a>
|
|
to avoid a memory leak.</p>
|
|
|
|
<p>The <a href="#sqlite3_snapshot_get">sqlite3_snapshot_get()</a> interface is only available when the
|
|
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> compile-time option is used.
|
|
</p><hr><a name="sqlite3_snapshot_open"></a>
|
|
<h2>Start a read transaction on an historical snapshot</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_snapshot_open(
|
|
sqlite3 *db,
|
|
const char *zSchema,
|
|
sqlite3_snapshot *pSnapshot
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open(D,S,P)</a> interface either starts a new read
|
|
transaction or upgrades an existing one for schema S of
|
|
<a href="#sqlite3">database connection</a> D such that the read transaction refers to
|
|
historical <a href="#sqlite3_snapshot">snapshot</a> P, rather than the most recent change to the
|
|
database. The <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open()</a> interface returns SQLITE_OK
|
|
on success or an appropriate <a href="rescode.html">error code</a> if it fails.</p>
|
|
|
|
<p>In order to succeed, the database connection must not be in
|
|
<a href="#sqlite3_get_autocommit">autocommit mode</a> when <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open(D,S,P)</a> is called. If there
|
|
is already a read transaction open on schema S, then the database handle
|
|
must have no active statements (SELECT statements that have been passed
|
|
to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
|
|
SQLITE_ERROR is returned if either of these conditions is violated, or
|
|
if schema S does not exist, or if the snapshot object is invalid.</p>
|
|
|
|
<p>A call to sqlite3_snapshot_open() will fail to open if the specified
|
|
snapshot has been overwritten by a <a href="wal.html#ckpt">checkpoint</a>. In this case
|
|
SQLITE_ERROR_SNAPSHOT is returned.</p>
|
|
|
|
<p>If there is already a read transaction open when this function is
|
|
invoked, then the same read transaction remains open (on the same
|
|
database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
|
|
is returned. If another error code - for example SQLITE_PROTOCOL or an
|
|
SQLITE_IOERR error code - is returned, then the final state of the
|
|
read transaction is undefined. If SQLITE_OK is returned, then the
|
|
read transaction is now open on database snapshot P.</p>
|
|
|
|
<p>A call to <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open(D,S,P)</a> will fail if the
|
|
database connection D does not know that the database file for
|
|
schema S is in <a href="wal.html">WAL mode</a>. A database connection might not know
|
|
that the database file is in <a href="wal.html">WAL mode</a> if there has been no prior
|
|
I/O on that database connection, or if the database entered <a href="wal.html">WAL mode</a>
|
|
after the most recent I/O on the database connection.
|
|
(Hint: Run "<a href="pragma.html#pragma_application_id">PRAGMA application_id</a>" against a newly opened
|
|
database connection in order to make it ready to use snapshots.)</p>
|
|
|
|
<p>The <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open()</a> interface is only available when the
|
|
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> compile-time option is used.
|
|
</p><hr><a name="sqlite3_snapshot_recover"></a>
|
|
<h2>Recover snapshots from a wal file</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
|
|
</pre></blockquote>
|
|
<p>
|
|
If a <a href="wal.html#walfile">WAL file</a> remains on disk after all database connections close
|
|
(either through the use of the <a href="#sqlitefcntlpersistwal">SQLITE_FCNTL_PERSIST_WAL</a> <a href="#sqlite3_file_control">file control</a>
|
|
or because the last process to have the database opened exited without
|
|
calling <a href="#sqlite3_close">sqlite3_close()</a>) and a new connection is subsequently opened
|
|
on that database and <a href="wal.html#walfile">WAL file</a>, the <a href="#sqlite3_snapshot_open">sqlite3_snapshot_open()</a> interface
|
|
will only be able to open the last transaction added to the WAL file
|
|
even though the WAL file contains other valid transactions.</p>
|
|
|
|
<p>This function attempts to scan the WAL file associated with database zDb
|
|
of database handle db and make all valid snapshots available to
|
|
sqlite3_snapshot_open(). It is an error if there is already a read
|
|
transaction open on the database, or if the database is not a WAL mode
|
|
database.</p>
|
|
|
|
<p>SQLITE_OK is returned if successful, or an SQLite error code otherwise.</p>
|
|
|
|
<p>This interface is only available if SQLite is compiled with the
|
|
<a href="compile.html#enable_snapshot">SQLITE_ENABLE_SNAPSHOT</a> option.
|
|
</p><hr><a name="sqlite3_soft_heap_limit"></a>
|
|
<h2>Deprecated Soft Heap Limit Interface</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_soft_heap_limit(int N);
|
|
</pre></blockquote>
|
|
<p>
|
|
This is a deprecated version of the <a href="#sqlite3_hard_heap_limit64">sqlite3_soft_heap_limit64()</a>
|
|
interface. This routine is provided for historical compatibility
|
|
only. All new applications should use the
|
|
<a href="#sqlite3_hard_heap_limit64">sqlite3_soft_heap_limit64()</a> interface rather than this one.
|
|
</p><hr><a name="sqlite3_step"></a>
|
|
<h2>Evaluate An SQL Statement</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_step(sqlite3_stmt*);
|
|
</pre></blockquote>
|
|
<p>
|
|
After a <a href="#sqlite3_stmt">prepared statement</a> has been prepared using any of
|
|
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>, <a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a>,
|
|
or <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a> or one of the legacy
|
|
interfaces <a href="#sqlite3_prepare">sqlite3_prepare()</a> or <a href="#sqlite3_prepare">sqlite3_prepare16()</a>, this function
|
|
must be called one or more times to evaluate the statement.</p>
|
|
|
|
<p>The details of the behavior of the sqlite3_step() interface depend
|
|
on whether the statement was prepared using the newer "vX" interfaces
|
|
<a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>, <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>,
|
|
<a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a> or the older legacy
|
|
interfaces <a href="#sqlite3_prepare">sqlite3_prepare()</a> and <a href="#sqlite3_prepare">sqlite3_prepare16()</a>. The use of the
|
|
new "vX" interface is recommended for new applications but the legacy
|
|
interface will continue to be supported.</p>
|
|
|
|
<p>In the legacy interface, the return value will be either <a href="#SQLITE_ABORT">SQLITE_BUSY</a>,
|
|
<a href="#SQLITE_ABORT">SQLITE_DONE</a>, <a href="#SQLITE_ABORT">SQLITE_ROW</a>, <a href="#SQLITE_ABORT">SQLITE_ERROR</a>, or <a href="#SQLITE_ABORT">SQLITE_MISUSE</a>.
|
|
With the "v2" interface, any of the other <a href="rescode.html">result codes</a> or
|
|
<a href="rescode.html#extrc">extended result codes</a> might be returned as well.</p>
|
|
|
|
<p><a href="#SQLITE_ABORT">SQLITE_BUSY</a> means that the database engine was unable to acquire the
|
|
database locks it needs to do its job. If the statement is a <a href="lang_transaction.html">COMMIT</a>
|
|
or occurs outside of an explicit transaction, then you can retry the
|
|
statement. If the statement is not a <a href="lang_transaction.html">COMMIT</a> and occurs within an
|
|
explicit transaction then you should rollback the transaction before
|
|
continuing.</p>
|
|
|
|
<p><a href="#SQLITE_ABORT">SQLITE_DONE</a> means that the statement has finished executing
|
|
successfully. sqlite3_step() should not be called again on this virtual
|
|
machine without first calling <a href="#sqlite3_reset">sqlite3_reset()</a> to reset the virtual
|
|
machine back to its initial state.</p>
|
|
|
|
<p>If the SQL statement being executed returns any data, then <a href="#SQLITE_ABORT">SQLITE_ROW</a>
|
|
is returned each time a new row of data is ready for processing by the
|
|
caller. The values may be accessed using the <a href="#sqlite3_column_blob">column access functions</a>.
|
|
sqlite3_step() is called again to retrieve the next row of data.</p>
|
|
|
|
<p><a href="#SQLITE_ABORT">SQLITE_ERROR</a> means that a run-time error (such as a constraint
|
|
violation) has occurred. sqlite3_step() should not be called again on
|
|
the VM. More information may be found by calling <a href="#sqlite3_errcode">sqlite3_errmsg()</a>.
|
|
With the legacy interface, a more specific error code (for example,
|
|
<a href="#SQLITE_ABORT">SQLITE_INTERRUPT</a>, <a href="#SQLITE_ABORT">SQLITE_SCHEMA</a>, <a href="#SQLITE_ABORT">SQLITE_CORRUPT</a>, and so forth)
|
|
can be obtained by calling <a href="#sqlite3_reset">sqlite3_reset()</a> on the
|
|
<a href="#sqlite3_stmt">prepared statement</a>. In the "v2" interface,
|
|
the more specific error code is returned directly by sqlite3_step().</p>
|
|
|
|
<p><a href="#SQLITE_ABORT">SQLITE_MISUSE</a> means that the this routine was called inappropriately.
|
|
Perhaps it was called on a <a href="#sqlite3_stmt">prepared statement</a> that has
|
|
already been <a href="#sqlite3_finalize">finalized</a> or on one that had
|
|
previously returned <a href="#SQLITE_ABORT">SQLITE_ERROR</a> or <a href="#SQLITE_ABORT">SQLITE_DONE</a>. Or it could
|
|
be the case that the same database connection is being used by two or
|
|
more threads at the same moment in time.</p>
|
|
|
|
<p>For all versions of SQLite up to and including 3.6.23.1, a call to
|
|
<a href="#sqlite3_reset">sqlite3_reset()</a> was required after sqlite3_step() returned anything
|
|
other than <a href="#SQLITE_ABORT">SQLITE_ROW</a> before any subsequent invocation of
|
|
sqlite3_step(). Failure to reset the prepared statement using
|
|
<a href="#sqlite3_reset">sqlite3_reset()</a> would result in an <a href="#SQLITE_ABORT">SQLITE_MISUSE</a> return from
|
|
sqlite3_step(). But after <a href="releaselog/3_6_23_1.html">version 3.6.23.1</a> (2010-03-26,
|
|
sqlite3_step() began
|
|
calling <a href="#sqlite3_reset">sqlite3_reset()</a> automatically in this circumstance rather
|
|
than returning <a href="#SQLITE_ABORT">SQLITE_MISUSE</a>. This is not considered a compatibility
|
|
break because any application that ever receives an SQLITE_MISUSE error
|
|
is broken by definition. The <a href="compile.html#omit_autoreset">SQLITE_OMIT_AUTORESET</a> compile-time option
|
|
can be used to restore the legacy behavior.</p>
|
|
|
|
<p><b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
|
|
API always returns a generic error code, <a href="#SQLITE_ABORT">SQLITE_ERROR</a>, following any
|
|
error other than <a href="#SQLITE_ABORT">SQLITE_BUSY</a> and <a href="#SQLITE_ABORT">SQLITE_MISUSE</a>. You must call
|
|
<a href="#sqlite3_reset">sqlite3_reset()</a> or <a href="#sqlite3_finalize">sqlite3_finalize()</a> in order to find one of the
|
|
specific <a href="rescode.html">error codes</a> that better describes the error.
|
|
We admit that this is a goofy design. The problem has been fixed
|
|
with the "v2" interface. If you prepare all of your SQL statements
|
|
using <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a> or <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>
|
|
or <a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a> or <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a> instead
|
|
of the legacy <a href="#sqlite3_prepare">sqlite3_prepare()</a> and <a href="#sqlite3_prepare">sqlite3_prepare16()</a> interfaces,
|
|
then the more specific <a href="rescode.html">error codes</a> are returned directly
|
|
by sqlite3_step(). The use of the "vX" interfaces is recommended.
|
|
</p><hr><a name="sqlite3_stmt_busy"></a>
|
|
<h2>Determine If A Prepared Statement Has Been Reset</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_stmt_busy(sqlite3_stmt*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
|
|
<a href="#sqlite3_stmt">prepared statement</a> S has been stepped at least once using
|
|
<a href="#sqlite3_step">sqlite3_step(S)</a> but has neither run to completion (returned
|
|
<a href="#SQLITE_ABORT">SQLITE_DONE</a> from <a href="#sqlite3_step">sqlite3_step(S)</a>) nor
|
|
been reset using <a href="#sqlite3_reset">sqlite3_reset(S)</a>. The sqlite3_stmt_busy(S)
|
|
interface returns false if S is a NULL pointer. If S is not a
|
|
NULL pointer and is not a pointer to a valid <a href="#sqlite3_stmt">prepared statement</a>
|
|
object, then the behavior is undefined and probably undesirable.</p>
|
|
|
|
<p>This interface can be used in combination <a href="#sqlite3_next_stmt">sqlite3_next_stmt()</a>
|
|
to locate all prepared statements associated with a database
|
|
connection that are in need of being reset. This can be used,
|
|
for example, in diagnostic routines to search for prepared
|
|
statements that are holding a transaction open.
|
|
</p><hr><a name="sqlite3_stmt_isexplain"></a>
|
|
<h2>Query The EXPLAIN Setting For A Prepared Statement</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_stmt_isexplain(S) interface returns 1 if the
|
|
prepared statement S is an EXPLAIN statement, or 2 if the
|
|
statement S is an EXPLAIN QUERY PLAN.
|
|
The sqlite3_stmt_isexplain(S) interface returns 0 if S is
|
|
an ordinary statement or a NULL pointer.
|
|
</p><hr><a name="sqlite3_stmt_readonly"></a>
|
|
<h2>Determine If An SQL Statement Writes The Database</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
|
|
and only if the <a href="#sqlite3_stmt">prepared statement</a> X makes no direct changes to
|
|
the content of the database file.</p>
|
|
|
|
<p>Note that <a href="appfunc.html">application-defined SQL functions</a> or
|
|
<a href="vtab.html">virtual tables</a> might change the database indirectly as a side effect.
|
|
For example, if an application defines a function "eval()" that
|
|
calls <a href="#sqlite3_exec">sqlite3_exec()</a>, then the following SQL statement would
|
|
change the database file through side-effects:</p>
|
|
|
|
<p><blockquote><pre>
|
|
SELECT eval('DELETE FROM t1') FROM t2;
|
|
</pre></blockquote></p>
|
|
|
|
<p>But because the <a href="lang_select.html">SELECT</a> statement does not change the database file
|
|
directly, sqlite3_stmt_readonly() would still return true.</p>
|
|
|
|
<p>Transaction control statements such as <a href="lang_transaction.html">BEGIN</a>, <a href="lang_transaction.html">COMMIT</a>, <a href="lang_transaction.html">ROLLBACK</a>,
|
|
<a href="lang_savepoint.html">SAVEPOINT</a>, and <a href="lang_savepoint.html">RELEASE</a> cause sqlite3_stmt_readonly() to return true,
|
|
since the statements themselves do not actually modify the database but
|
|
rather they control the timing of when other statements modify the
|
|
database. The <a href="lang_attach.html">ATTACH</a> and <a href="lang_detach.html">DETACH</a> statements also cause
|
|
sqlite3_stmt_readonly() to return true since, while those statements
|
|
change the configuration of a database connection, they do not make
|
|
changes to the content of the database files on disk.
|
|
The sqlite3_stmt_readonly() interface returns true for <a href="lang_transaction.html">BEGIN</a> since
|
|
<a href="lang_transaction.html">BEGIN</a> merely sets internal flags, but the <a href="lang_transaction.html">BEGIN IMMEDIATE</a> and
|
|
<a href="lang_transaction.html">BEGIN EXCLUSIVE</a> commands do touch the database and so
|
|
sqlite3_stmt_readonly() returns false for those commands.
|
|
</p><hr><a name="sqlite3_stmt_scanstatus"></a>
|
|
<h2>Prepared Statement Scan Status</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_stmt_scanstatus(
|
|
sqlite3_stmt *pStmt, /* Prepared statement for which info desired */
|
|
int idx, /* Index of loop to report on */
|
|
int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */
|
|
void *pOut /* Result written here */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
This interface returns information about the predicted and measured
|
|
performance for pStmt. Advanced applications can use this
|
|
interface to compare the predicted and the measured performance and
|
|
issue warnings and/or rerun <a href="lang_analyze.html">ANALYZE</a> if discrepancies are found.</p>
|
|
|
|
<p>Since this interface is expected to be rarely used, it is only
|
|
available if SQLite is compiled using the <a href="compile.html#enable_stmt_scanstatus">SQLITE_ENABLE_STMT_SCANSTATUS</a>
|
|
compile-time option.</p>
|
|
|
|
<p>The "iScanStatusOp" parameter determines which status information to return.
|
|
The "iScanStatusOp" must be one of the <a href="#SQLITE_SCANSTAT_EST">scanstatus options</a> or the behavior
|
|
of this interface is undefined.
|
|
The requested measurement is written into a variable pointed to by
|
|
the "pOut" parameter.
|
|
Parameter "idx" identifies the specific loop to retrieve statistics for.
|
|
Loops are numbered starting from zero. If idx is out of range - less than
|
|
zero or greater than or equal to the total number of loops used to implement
|
|
the statement - a non-zero value is returned and the variable that pOut
|
|
points to is unchanged.</p>
|
|
|
|
<p>Statistics might not be available for all loops in all statements. In cases
|
|
where there exist loops with no available statistics, this function behaves
|
|
as if the loop did not exist - it returns non-zero and leave the variable
|
|
that pOut points to unchanged.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_stmt_scanstatus_reset">sqlite3_stmt_scanstatus_reset()</a>
|
|
</p><hr><a name="sqlite3_stmt_scanstatus_reset"></a>
|
|
<h2>Zero Scan-Status Counters</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
|
|
</pre></blockquote>
|
|
<p>
|
|
Zero all <a href="#sqlite3_stmt_scanstatus">sqlite3_stmt_scanstatus()</a> related event counters.</p>
|
|
|
|
<p>This API is only available if the library is built with pre-processor
|
|
symbol <a href="compile.html#enable_stmt_scanstatus">SQLITE_ENABLE_STMT_SCANSTATUS</a> defined.
|
|
</p><hr><a name="sqlite3_stmt_status"></a>
|
|
<h2>Prepared Statement Status</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
|
|
</pre></blockquote>
|
|
<p>
|
|
Each prepared statement maintains various
|
|
<a href="#SQLITE_STMTSTATUS counter">SQLITE_STMTSTATUS counters</a> that measure the number
|
|
of times it has performed specific operations. These counters can
|
|
be used to monitor the performance characteristics of the prepared
|
|
statements. For example, if the number of table steps greatly exceeds
|
|
the number of table searches or result rows, that would tend to indicate
|
|
that the prepared statement is using a full table scan rather than
|
|
an index.</p>
|
|
|
|
<p>This interface is used to retrieve and reset counter values from
|
|
a <a href="#sqlite3_stmt">prepared statement</a>. The first argument is the prepared statement
|
|
object to be interrogated. The second argument
|
|
is an integer code for a specific <a href="#SQLITE_STMTSTATUS counter">SQLITE_STMTSTATUS counter</a>
|
|
to be interrogated.
|
|
The current value of the requested counter is returned.
|
|
If the resetFlg is true, then the counter is reset to zero after this
|
|
interface call returns.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_status">sqlite3_status()</a> and <a href="#sqlite3_db_status">sqlite3_db_status()</a>.
|
|
</p><hr><a name="sqlite3_str_finish"></a>
|
|
<h2>Finalize A Dynamic String</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
char *sqlite3_str_finish(sqlite3_str*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a> interface destroys the sqlite3_str object X
|
|
and returns a pointer to a memory buffer obtained from <a href="#sqlite3_free">sqlite3_malloc64()</a>
|
|
that contains the constructed string. The calling application should
|
|
pass the returned value to <a href="#sqlite3_free">sqlite3_free()</a> to avoid a memory leak.
|
|
The <a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a> interface may return a NULL pointer if any
|
|
errors were encountered during construction of the string. The
|
|
<a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a> interface will also return a NULL pointer if the
|
|
string in <a href="#sqlite3_str">sqlite3_str</a> object X is zero bytes long.
|
|
</p><hr><a name="sqlite3_str_new"></a>
|
|
<h2>Create A New Dynamic String Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_str *sqlite3_str_new(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> interface allocates and initializes
|
|
a new <a href="#sqlite3_str">sqlite3_str</a> object. To avoid memory leaks, the object returned by
|
|
<a href="#sqlite3_str_new">sqlite3_str_new()</a> must be freed by a subsequent call to
|
|
<a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a>.</p>
|
|
|
|
<p>The <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> interface always returns a pointer to a
|
|
valid <a href="#sqlite3_str">sqlite3_str</a> object, though in the event of an out-of-memory
|
|
error the returned object might be a special singleton that will
|
|
silently reject new text, always return SQLITE_NOMEM from
|
|
<a href="#sqlite3_str_errcode">sqlite3_str_errcode()</a>, always return 0 for
|
|
<a href="#sqlite3_str_errcode">sqlite3_str_length()</a>, and always return NULL from
|
|
<a href="#sqlite3_str_finish">sqlite3_str_finish(X)</a>. It is always safe to use the value
|
|
returned by <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> as the sqlite3_str parameter
|
|
to any of the other <a href="#sqlite3_str">sqlite3_str</a> methods.</p>
|
|
|
|
<p>The D parameter to <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> may be NULL. If the
|
|
D parameter in <a href="#sqlite3_str_new">sqlite3_str_new(D)</a> is not NULL, then the maximum
|
|
length of the string contained in the <a href="#sqlite3_str">sqlite3_str</a> object will be
|
|
the value set for <a href="#sqlite3_limit">sqlite3_limit</a>(D,<a href="#sqlitelimitlength">SQLITE_LIMIT_LENGTH</a>) instead
|
|
of <a href="limits.html#max_length">SQLITE_MAX_LENGTH</a>.
|
|
</p><hr><a name="sqlite3_strglob"></a>
|
|
<h2>String Globbing</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_strglob(const char *zGlob, const char *zStr);
|
|
</pre></blockquote>
|
|
<p>The <a href="#sqlite3_strglob">sqlite3_strglob(P,X)</a> interface returns zero if and only if
|
|
string X matches the <a href="lang_expr.html#glob">GLOB</a> pattern P.
|
|
The definition of <a href="lang_expr.html#glob">GLOB</a> pattern matching used in
|
|
<a href="#sqlite3_strglob">sqlite3_strglob(P,X)</a> is the same as for the "X GLOB P" operator in the
|
|
SQL dialect understood by SQLite. The <a href="#sqlite3_strglob">sqlite3_strglob(P,X)</a> function
|
|
is case sensitive.</p>
|
|
|
|
<p>Note that this routine returns zero on a match and non-zero if the strings
|
|
do not match, the same as <a href="#sqlite3_stricmp">sqlite3_stricmp()</a> and <a href="#sqlite3_stricmp">sqlite3_strnicmp()</a>.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_strlike">sqlite3_strlike()</a>.
|
|
</p><hr><a name="sqlite3_strlike"></a>
|
|
<h2>String LIKE Matching</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
|
|
</pre></blockquote>
|
|
<p>The <a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> interface returns zero if and only if
|
|
string X matches the <a href="lang_expr.html#like">LIKE</a> pattern P with escape character E.
|
|
The definition of <a href="lang_expr.html#like">LIKE</a> pattern matching used in
|
|
<a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> is the same as for the "X LIKE P ESCAPE E"
|
|
operator in the SQL dialect understood by SQLite. For "X LIKE P" without
|
|
the ESCAPE clause, set the E parameter of <a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> to 0.
|
|
As with the LIKE operator, the <a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> function is case
|
|
insensitive - equivalent upper and lower case ASCII characters match
|
|
one another.</p>
|
|
|
|
<p>The <a href="#sqlite3_strlike">sqlite3_strlike(P,X,E)</a> function matches Unicode characters, though
|
|
only ASCII characters are case folded.</p>
|
|
|
|
<p>Note that this routine returns zero on a match and non-zero if the strings
|
|
do not match, the same as <a href="#sqlite3_stricmp">sqlite3_stricmp()</a> and <a href="#sqlite3_stricmp">sqlite3_strnicmp()</a>.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_strglob">sqlite3_strglob()</a>.
|
|
</p><hr><a name="sqlite3_system_errno"></a>
|
|
<h2>Low-level system error code</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_system_errno(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
Attempt to return the underlying operating system error code or error
|
|
number that caused the most recent I/O error or failure to open a file.
|
|
The return value is OS-dependent. For example, on unix systems, after
|
|
<a href="#sqlite3_open">sqlite3_open_v2()</a> returns <a href="#SQLITE_ABORT">SQLITE_CANTOPEN</a>, this interface could be
|
|
called to get back the underlying "errno" that caused the problem, such
|
|
as ENOSPC, EAUTH, EISDIR, and so forth.
|
|
</p><hr><a name="sqlite3_table_column_metadata"></a>
|
|
<h2>Extract Metadata About A Column Of A Table</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_table_column_metadata(
|
|
sqlite3 *db, /* Connection handle */
|
|
const char *zDbName, /* Database name or NULL */
|
|
const char *zTableName, /* Table name */
|
|
const char *zColumnName, /* Column name */
|
|
char const **pzDataType, /* OUTPUT: Declared data type */
|
|
char const **pzCollSeq, /* OUTPUT: Collation sequence name */
|
|
int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */
|
|
int *pPrimaryKey, /* OUTPUT: True if column part of PK */
|
|
int *pAutoinc /* OUTPUT: True if column is auto-increment */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
|
|
information about column C of table T in database D
|
|
on <a href="#sqlite3">database connection</a> X. The sqlite3_table_column_metadata()
|
|
interface returns SQLITE_OK and fills in the non-NULL pointers in
|
|
the final five arguments with appropriate values if the specified
|
|
column exists. The sqlite3_table_column_metadata() interface returns
|
|
SQLITE_ERROR if the specified column does not exist.
|
|
If the column-name parameter to sqlite3_table_column_metadata() is a
|
|
NULL pointer, then this routine simply checks for the existence of the
|
|
table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
|
|
does not. If the table name parameter T in a call to
|
|
sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
|
|
undefined behavior.</p>
|
|
|
|
<p>The column is identified by the second, third and fourth parameters to
|
|
this function. The second parameter is either the name of the database
|
|
(i.e. "main", "temp", or an attached database) containing the specified
|
|
table or NULL. If it is NULL, then all attached databases are searched
|
|
for the table using the same algorithm used by the database engine to
|
|
resolve unqualified table references.</p>
|
|
|
|
<p>The third and fourth parameters to this function are the table and column
|
|
name of the desired column, respectively.</p>
|
|
|
|
<p>Metadata is returned by writing to the memory locations passed as the 5th
|
|
and subsequent parameters to this function. Any of these arguments may be
|
|
NULL, in which case the corresponding element of metadata is omitted.</p>
|
|
|
|
<p><blockquote>
|
|
<table border="1">
|
|
<tr><th> Parameter <th> Output<br>Type <th> Description</p>
|
|
|
|
<p><tr><td> 5th <td> const char* <td> Data type
|
|
<tr><td> 6th <td> const char* <td> Name of default collation sequence
|
|
<tr><td> 7th <td> int <td> True if column has a NOT NULL constraint
|
|
<tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY
|
|
<tr><td> 9th <td> int <td> True if column is <a href="autoinc.html">AUTOINCREMENT</a>
|
|
</table>
|
|
</blockquote></p>
|
|
|
|
<p>The memory pointed to by the character pointers returned for the
|
|
declaration type and collation sequence is valid until the next
|
|
call to any SQLite API function.</p>
|
|
|
|
<p>If the specified table is actually a view, an <a href="rescode.html">error code</a> is returned.</p>
|
|
|
|
<p>If the specified column is "rowid", "oid" or "_rowid_" and the table
|
|
is not a <a href="withoutrowid.html">WITHOUT ROWID</a> table and an
|
|
<a href="lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> column has been explicitly declared, then the output
|
|
parameters are set for the explicitly declared column. If there is no
|
|
<a href="lang_createtable.html#rowid">INTEGER PRIMARY KEY</a> column, then the outputs
|
|
for the <a href="lang_createtable.html#rowid">rowid</a> are set as follows:</p>
|
|
|
|
<p><pre>
|
|
data type: "INTEGER"
|
|
collation sequence: "BINARY"
|
|
not null: 0
|
|
primary key: 1
|
|
auto increment: 0
|
|
</pre></p>
|
|
|
|
<p>This function causes all database schemas to be read from disk and
|
|
parsed, if that has not already been done, and returns an error if
|
|
any errors are encountered while loading the schema.
|
|
</p><hr><a name="sqlite3_test_control"></a>
|
|
<h2>Testing Interface</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_test_control(int op, ...);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_test_control() interface is used to read out internal
|
|
state of SQLite and to inject faults into SQLite for testing
|
|
purposes. The first parameter is an operation code that determines
|
|
the number, meaning, and operation of all subsequent parameters.</p>
|
|
|
|
<p>This interface is not for use by applications. It exists solely
|
|
for verifying the correct operation of the SQLite library. Depending
|
|
on how the SQLite library is compiled, this interface might not exist.</p>
|
|
|
|
<p>The details of the operation codes, their meanings, the parameters
|
|
they take, and what they do are all subject to change without notice.
|
|
Unlike most of the SQLite API, this function is not guaranteed to
|
|
operate consistently from one release to the next.
|
|
</p><hr><a name="sqlite3_threadsafe"></a>
|
|
<h2>Test To See If The Library Is Threadsafe</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_threadsafe(void);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_threadsafe() function returns zero if and only if
|
|
SQLite was compiled with mutexing code omitted due to the
|
|
<a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> compile-time option being set to 0.</p>
|
|
|
|
<p>SQLite can be compiled with or without mutexes. When
|
|
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> C preprocessor macro is 1 or 2, mutexes
|
|
are enabled and SQLite is threadsafe. When the
|
|
<a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> macro is 0,
|
|
the mutexes are omitted. Without the mutexes, it is not safe
|
|
to use SQLite concurrently from more than one thread.</p>
|
|
|
|
<p>Enabling mutexes incurs a measurable performance penalty.
|
|
So if speed is of utmost importance, it makes sense to disable
|
|
the mutexes. But for maximum safety, mutexes should be enabled.
|
|
The default behavior is for mutexes to be enabled.</p>
|
|
|
|
<p>This interface can be used by an application to make sure that the
|
|
version of SQLite that it is linking against was compiled with
|
|
the desired setting of the <a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> macro.</p>
|
|
|
|
<p>This interface only reports on the compile-time mutex setting
|
|
of the <a href="compile.html#threadsafe">SQLITE_THREADSAFE</a> flag. If SQLite is compiled with
|
|
SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
|
|
can be fully or partially disabled using a call to <a href="#sqlite3_config">sqlite3_config()</a>
|
|
with the verbs <a href="#sqliteconfigsinglethread">SQLITE_CONFIG_SINGLETHREAD</a>, <a href="#sqliteconfigmultithread">SQLITE_CONFIG_MULTITHREAD</a>,
|
|
or <a href="#sqliteconfigserialized">SQLITE_CONFIG_SERIALIZED</a>. The return value of the
|
|
sqlite3_threadsafe() function shows only the compile-time setting of
|
|
thread safety, not any run-time changes to that setting made by
|
|
sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
|
|
is unchanged by calls to sqlite3_config().</p>
|
|
|
|
<p>See the <a href="threadsafe.html">threading mode</a> documentation for additional information.
|
|
</p><hr><a name="sqlite3_total_changes"></a>
|
|
<h2>Total Number Of Rows Modified</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_total_changes(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function returns the total number of rows inserted, modified or
|
|
deleted by all <a href="lang_insert.html">INSERT</a>, <a href="lang_update.html">UPDATE</a> or <a href="lang_delete.html">DELETE</a> statements completed
|
|
since the database connection was opened, including those executed as
|
|
part of trigger programs. Executing any other type of SQL statement
|
|
does not affect the value returned by sqlite3_total_changes().</p>
|
|
|
|
<p>Changes made as part of <a href="foreignkeys.html#fk_actions">foreign key actions</a> are included in the
|
|
count, but those made as part of REPLACE constraint resolution are
|
|
not. Changes to a view that are intercepted by INSTEAD OF triggers
|
|
are not counted.</p>
|
|
|
|
<p>The <a href="#sqlite3_total_changes">sqlite3_total_changes(D)</a> interface only reports the number
|
|
of rows that changed due to SQL statement run against database
|
|
connection D. Any changes by other database connections are ignored.
|
|
To detect changes against a database file from other database
|
|
connections use the <a href="pragma.html#pragma_data_version">PRAGMA data_version</a> command or the
|
|
<a href="#sqlitefcntldataversion">SQLITE_FCNTL_DATA_VERSION</a> <a href="#sqlite3_file_control">file control</a>.</p>
|
|
|
|
<p>If a separate thread makes changes on the same database connection
|
|
while <a href="#sqlite3_total_changes">sqlite3_total_changes()</a> is running then the value
|
|
returned is unpredictable and not meaningful.</p>
|
|
|
|
<p>See also:
|
|
<ul>
|
|
<li> the <a href="#sqlite3_changes">sqlite3_changes()</a> interface
|
|
<li> the <a href="pragma.html#pragma_count_changes">count_changes pragma</a>
|
|
<li> the <a href="lang_corefunc.html#changes">changes() SQL function</a>
|
|
<li> the <a href="pragma.html#pragma_data_version">data_version pragma</a>
|
|
<li> the <a href="#sqlitefcntldataversion">SQLITE_FCNTL_DATA_VERSION</a> <a href="#sqlite3_file_control">file control</a>
|
|
</ul>
|
|
</p><hr><a name="sqlite3_trace_v2"></a>
|
|
<h2>SQL Trace Hook</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_trace_v2(
|
|
sqlite3*,
|
|
unsigned uMask,
|
|
int(*xCallback)(unsigned,void*,void*,void*),
|
|
void *pCtx
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
|
|
function X against <a href="#sqlite3">database connection</a> D, using property mask M
|
|
and context pointer P. If the X callback is
|
|
NULL or if the M mask is zero, then tracing is disabled. The
|
|
M argument should be the bitwise OR-ed combination of
|
|
zero or more <a href="#SQLITE_TRACE">SQLITE_TRACE</a> constants.</p>
|
|
|
|
<p>Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides
|
|
(cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().</p>
|
|
|
|
<p>The X callback is invoked whenever any of the events identified by
|
|
mask M occur. The integer return value from the callback is currently
|
|
ignored, though this may change in future releases. Callback
|
|
implementations should return zero to ensure future compatibility.</p>
|
|
|
|
<p>A trace callback is invoked with four arguments: callback(T,C,P,X).
|
|
The T argument is one of the <a href="#SQLITE_TRACE">SQLITE_TRACE</a>
|
|
constants to indicate why the callback was invoked.
|
|
The C argument is a copy of the context pointer.
|
|
The P and X arguments are pointers whose meanings depend on T.</p>
|
|
|
|
<p>The sqlite3_trace_v2() interface is intended to replace the legacy
|
|
interfaces <a href="#sqlite3_profile">sqlite3_trace()</a> and <a href="#sqlite3_profile">sqlite3_profile()</a>, both of which
|
|
are deprecated.
|
|
</p><hr><a name="sqlite3_unlock_notify"></a>
|
|
<h2>Unlock Notification</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_unlock_notify(
|
|
sqlite3 *pBlocked, /* Waiting connection */
|
|
void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */
|
|
void *pNotifyArg /* Argument to pass to xNotify */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
When running in shared-cache mode, a database operation may fail with
|
|
an <a href="#SQLITE_ABORT">SQLITE_LOCKED</a> error if the required locks on the shared-cache or
|
|
individual tables within the shared-cache cannot be obtained. See
|
|
<a href="sharedcache.html">SQLite Shared-Cache Mode</a> for a description of shared-cache locking.
|
|
This API may be used to register a callback that SQLite will invoke
|
|
when the connection currently holding the required lock relinquishes it.
|
|
This API is only available if the library was compiled with the
|
|
<a href="compile.html#enable_unlock_notify">SQLITE_ENABLE_UNLOCK_NOTIFY</a> C-preprocessor symbol defined.</p>
|
|
|
|
<p>See Also: <a href="unlock_notify.html">Using the SQLite Unlock Notification Feature</a>.</p>
|
|
|
|
<p>Shared-cache locks are released when a database connection concludes
|
|
its current transaction, either by committing it or rolling it back.</p>
|
|
|
|
<p>When a connection (known as the blocked connection) fails to obtain a
|
|
shared-cache lock and SQLITE_LOCKED is returned to the caller, the
|
|
identity of the database connection (the blocking connection) that
|
|
has locked the required resource is stored internally. After an
|
|
application receives an SQLITE_LOCKED error, it may call the
|
|
sqlite3_unlock_notify() method with the blocked connection handle as
|
|
the first argument to register for a callback that will be invoked
|
|
when the blocking connections current transaction is concluded. The
|
|
callback is invoked from within the <a href="#sqlite3_step">sqlite3_step</a> or <a href="#sqlite3_close">sqlite3_close</a>
|
|
call that concludes the blocking connection's transaction.</p>
|
|
|
|
<p>If sqlite3_unlock_notify() is called in a multi-threaded application,
|
|
there is a chance that the blocking connection will have already
|
|
concluded its transaction by the time sqlite3_unlock_notify() is invoked.
|
|
If this happens, then the specified callback is invoked immediately,
|
|
from within the call to sqlite3_unlock_notify().</p>
|
|
|
|
<p>If the blocked connection is attempting to obtain a write-lock on a
|
|
shared-cache table, and more than one other connection currently holds
|
|
a read-lock on the same table, then SQLite arbitrarily selects one of
|
|
the other connections to use as the blocking connection.</p>
|
|
|
|
<p>There may be at most one unlock-notify callback registered by a
|
|
blocked connection. If sqlite3_unlock_notify() is called when the
|
|
blocked connection already has a registered unlock-notify callback,
|
|
then the new callback replaces the old. If sqlite3_unlock_notify() is
|
|
called with a NULL pointer as its second argument, then any existing
|
|
unlock-notify callback is canceled. The blocked connections
|
|
unlock-notify callback may also be canceled by closing the blocked
|
|
connection using <a href="#sqlite3_close">sqlite3_close()</a>.</p>
|
|
|
|
<p>The unlock-notify callback is not reentrant. If an application invokes
|
|
any sqlite3_xxx API functions from within an unlock-notify callback, a
|
|
crash or deadlock may be the result.</p>
|
|
|
|
<p>Unless deadlock is detected (see below), sqlite3_unlock_notify() always
|
|
returns SQLITE_OK.</p>
|
|
|
|
<p><b>Callback Invocation Details</b></p>
|
|
|
|
<p>When an unlock-notify callback is registered, the application provides a
|
|
single void* pointer that is passed to the callback when it is invoked.
|
|
However, the signature of the callback function allows SQLite to pass
|
|
it an array of void* context pointers. The first argument passed to
|
|
an unlock-notify callback is a pointer to an array of void* pointers,
|
|
and the second is the number of entries in the array.</p>
|
|
|
|
<p>When a blocking connection's transaction is concluded, there may be
|
|
more than one blocked connection that has registered for an unlock-notify
|
|
callback. If two or more such blocked connections have specified the
|
|
same callback function, then instead of invoking the callback function
|
|
multiple times, it is invoked once with the set of void* context pointers
|
|
specified by the blocked connections bundled together into an array.
|
|
This gives the application an opportunity to prioritize any actions
|
|
related to the set of unblocked database connections.</p>
|
|
|
|
<p><b>Deadlock Detection</b></p>
|
|
|
|
<p>Assuming that after registering for an unlock-notify callback a
|
|
database waits for the callback to be issued before taking any further
|
|
action (a reasonable assumption), then using this API may cause the
|
|
application to deadlock. For example, if connection X is waiting for
|
|
connection Y's transaction to be concluded, and similarly connection
|
|
Y is waiting on connection X's transaction, then neither connection
|
|
will proceed and the system may remain deadlocked indefinitely.</p>
|
|
|
|
<p>To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
|
|
detection. If a given call to sqlite3_unlock_notify() would put the
|
|
system in a deadlocked state, then SQLITE_LOCKED is returned and no
|
|
unlock-notify callback is registered. The system is said to be in
|
|
a deadlocked state if connection A has registered for an unlock-notify
|
|
callback on the conclusion of connection B's transaction, and connection
|
|
B has itself registered for an unlock-notify callback when connection
|
|
A's transaction is concluded. Indirect deadlock is also detected, so
|
|
the system is also considered to be deadlocked if connection B has
|
|
registered for an unlock-notify callback on the conclusion of connection
|
|
C's transaction, where connection C is waiting on connection A. Any
|
|
number of levels of indirection are allowed.</p>
|
|
|
|
<p><b>The "DROP TABLE" Exception</b></p>
|
|
|
|
<p>When a call to <a href="#sqlite3_step">sqlite3_step()</a> returns SQLITE_LOCKED, it is almost
|
|
always appropriate to call sqlite3_unlock_notify(). There is however,
|
|
one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
|
|
SQLite checks if there are any currently executing SELECT statements
|
|
that belong to the same connection. If there are, SQLITE_LOCKED is
|
|
returned. In this case there is no "blocking connection", so invoking
|
|
sqlite3_unlock_notify() results in the unlock-notify callback being
|
|
invoked immediately. If the application then re-attempts the "DROP TABLE"
|
|
or "DROP INDEX" query, an infinite loop might be the result.</p>
|
|
|
|
<p>One way around this problem is to check the extended error code returned
|
|
by an sqlite3_step() call. If there is a blocking connection, then the
|
|
extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
|
|
the special "DROP TABLE/INDEX" case, the extended error code is just
|
|
SQLITE_LOCKED.
|
|
</p><hr><a name="sqlite3_update_hook"></a>
|
|
<h2>Data Change Notification Callbacks</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void *sqlite3_update_hook(
|
|
sqlite3*,
|
|
void(*)(void *,int ,char const *,char const *,sqlite3_int64),
|
|
void*
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_update_hook() interface registers a callback function
|
|
with the <a href="#sqlite3">database connection</a> identified by the first argument
|
|
to be invoked whenever a row is updated, inserted or deleted in
|
|
a <a href="rowidtable.html">rowid table</a>.
|
|
Any callback set by a previous call to this function
|
|
for the same database connection is overridden.</p>
|
|
|
|
<p>The second argument is a pointer to the function to invoke when a
|
|
row is updated, inserted or deleted in a rowid table.
|
|
The first argument to the callback is a copy of the third argument
|
|
to sqlite3_update_hook().
|
|
The second callback argument is one of <a href="#SQLITE_ALTER_TABLE">SQLITE_INSERT</a>, <a href="#SQLITE_ALTER_TABLE">SQLITE_DELETE</a>,
|
|
or <a href="#SQLITE_ALTER_TABLE">SQLITE_UPDATE</a>, depending on the operation that caused the callback
|
|
to be invoked.
|
|
The third and fourth arguments to the callback contain pointers to the
|
|
database and table name containing the affected row.
|
|
The final callback parameter is the <a href="lang_createtable.html#rowid">rowid</a> of the row.
|
|
In the case of an update, this is the <a href="lang_createtable.html#rowid">rowid</a> after the update takes place.</p>
|
|
|
|
<p>The update hook is not invoked when internal system tables are
|
|
modified (i.e. sqlite_sequence).
|
|
The update hook is not invoked when <a href="withoutrowid.html">WITHOUT ROWID</a> tables are modified.</p>
|
|
|
|
<p>In the current implementation, the update hook
|
|
is not invoked when conflicting rows are deleted because of an
|
|
<a href="lang_conflict.html">ON CONFLICT REPLACE</a> clause. Nor is the update hook
|
|
invoked when rows are deleted using the <a href="lang_delete.html#truncateopt">truncate optimization</a>.
|
|
The exceptions defined in this paragraph might change in a future
|
|
release of SQLite.</p>
|
|
|
|
<p>The update hook implementation must not do anything that will modify
|
|
the database connection that invoked the update hook. Any actions
|
|
to modify the database connection must be deferred until after the
|
|
completion of the <a href="#sqlite3_step">sqlite3_step()</a> call that triggered the update hook.
|
|
Note that <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and <a href="#sqlite3_step">sqlite3_step()</a> both modify their
|
|
database connections for the meaning of "modify" in this paragraph.</p>
|
|
|
|
<p>The sqlite3_update_hook(D,C,P) function
|
|
returns the P argument from the previous call
|
|
on the same <a href="#sqlite3">database connection</a> D, or NULL for
|
|
the first call on D.</p>
|
|
|
|
<p>See also the <a href="#sqlite3_commit_hook">sqlite3_commit_hook()</a>, <a href="#sqlite3_commit_hook">sqlite3_rollback_hook()</a>,
|
|
and <a href="#sqlite3_preupdate_count">sqlite3_preupdate_hook()</a> interfaces.
|
|
</p><hr><a name="sqlite3_user_data"></a>
|
|
<h2>User Data For Functions</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void *sqlite3_user_data(sqlite3_context*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_user_data() interface returns a copy of
|
|
the pointer that was the pUserData parameter (the 5th parameter)
|
|
of the <a href="#sqlite3_create_function">sqlite3_create_function()</a>
|
|
and <a href="#sqlite3_create_function">sqlite3_create_function16()</a> routines that originally
|
|
registered the application defined function.</p>
|
|
|
|
<p>This routine must be called from the same thread in which
|
|
the application-defined function is running.
|
|
</p><hr><a name="sqlite3_value_subtype"></a>
|
|
<h2>Finding The Subtype Of SQL Values</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
unsigned int sqlite3_value_subtype(sqlite3_value*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_value_subtype(V) function returns the subtype for
|
|
an <a href="appfunc.html">application-defined SQL function</a> argument V. The subtype
|
|
information can be used to pass a limited amount of context from
|
|
one SQL function to another. Use the <a href="#sqlite3_result_subtype">sqlite3_result_subtype()</a>
|
|
routine to set the subtype for the return value of an SQL function.
|
|
</p><hr><a name="sqlite3_vtab_collation"></a>
|
|
<h2>Determine The Collation For a Virtual Table Constraint</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function may only be called from within a call to the <a href="vtab.html#xbestindex">xBestIndex</a>
|
|
method of a <a href="vtab.html">virtual table</a>.</p>
|
|
|
|
<p>The first argument must be the sqlite3_index_info object that is the
|
|
first parameter to the xBestIndex() method. The second argument must be
|
|
an index into the aConstraint[] array belonging to the sqlite3_index_info
|
|
structure passed to xBestIndex. This function returns a pointer to a buffer
|
|
containing the name of the collation sequence for the corresponding
|
|
constraint.
|
|
</p><hr><a name="sqlite3_vtab_config"></a>
|
|
<h2>Virtual Table Interface Configuration</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_vtab_config(sqlite3*, int op, ...);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function may be called by either the <a href="vtab.html#xconnect">xConnect</a> or <a href="vtab.html#xcreate">xCreate</a> method
|
|
of a <a href="vtab.html">virtual table</a> implementation to configure
|
|
various facets of the virtual table interface.</p>
|
|
|
|
<p>If this interface is invoked outside the context of an xConnect or
|
|
xCreate virtual table method then the behavior is undefined.</p>
|
|
|
|
<p>In the call sqlite3_vtab_config(D,C,...) the D parameter is the
|
|
<a href="#sqlite3">database connection</a> in which the virtual table is being created and
|
|
which is passed in as the first argument to the <a href="vtab.html#xconnect">xConnect</a> or <a href="vtab.html#xcreate">xCreate</a>
|
|
method that is invoking sqlite3_vtab_config(). The C parameter is one
|
|
of the <a href="#SQLITE_VTAB_CONSTRAINT_SUPPORT">virtual table configuration options</a>. The presence and meaning
|
|
of parameters after C depend on which <a href="#SQLITE_VTAB_CONSTRAINT_SUPPORT">virtual table configuration option</a>
|
|
is used.
|
|
</p><hr><a name="sqlite3_vtab_nochange"></a>
|
|
<h2>Determine If Virtual Table Column Access Is For UPDATE</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_vtab_nochange(sqlite3_context*);
|
|
</pre></blockquote>
|
|
<p>
|
|
If the sqlite3_vtab_nochange(X) routine is called within the <a href="vtab.html#xcolumn">xColumn</a>
|
|
method of a <a href="vtab.html">virtual table</a>, then it returns true if and only if the
|
|
column is being fetched as part of an UPDATE operation during which the
|
|
column value will not change. Applications might use this to substitute
|
|
a return value that is less expensive to compute and that the corresponding
|
|
<a href="vtab.html#xupdate">xUpdate</a> method understands as a "no-change" value.</p>
|
|
|
|
<p>If the <a href="vtab.html#xcolumn">xColumn</a> method calls sqlite3_vtab_nochange() and finds that
|
|
the column is not changed by the UPDATE statement, then the xColumn
|
|
method can optionally return without setting a result, without calling
|
|
any of the <a href="#sqlite3_result_blob">sqlite3_result_xxxxx() interfaces</a>.
|
|
In that case, <a href="#sqlite3_value_blob">sqlite3_value_nochange(X)</a> will return true for the
|
|
same column in the <a href="vtab.html#xupdate">xUpdate</a> method.
|
|
</p><hr><a name="sqlite3_vtab_on_conflict"></a>
|
|
<h2>Determine The Virtual Table Conflict Policy</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_vtab_on_conflict(sqlite3 *);
|
|
</pre></blockquote>
|
|
<p>
|
|
This function may only be called from within a call to the <a href="vtab.html#xupdate">xUpdate</a> method
|
|
of a <a href="vtab.html">virtual table</a> implementation for an INSERT or UPDATE operation. The
|
|
value returned is one of <a href="#SQLITE_FAIL">SQLITE_ROLLBACK</a>, <a href="#SQLITE_DENY">SQLITE_IGNORE</a>, <a href="#SQLITE_FAIL">SQLITE_FAIL</a>,
|
|
<a href="#SQLITE_ABORT">SQLITE_ABORT</a>, or <a href="#SQLITE_FAIL">SQLITE_REPLACE</a>, according to the <a href="lang_conflict.html">ON CONFLICT</a> mode
|
|
of the SQL statement that triggered the call to the <a href="vtab.html#xupdate">xUpdate</a> method of the
|
|
<a href="vtab.html">virtual table</a>.
|
|
</p><hr><a name="sqlite3_wal_autocheckpoint"></a>
|
|
<h2>Configure an auto-checkpoint</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_wal_autocheckpoint">sqlite3_wal_autocheckpoint(D,N)</a> is a wrapper around
|
|
<a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> that causes any database on <a href="#sqlite3">database connection</a> D
|
|
to automatically <a href="wal.html#ckpt">checkpoint</a>
|
|
after committing a transaction if there are N or
|
|
more frames in the <a href="wal.html">write-ahead log</a> file. Passing zero or
|
|
a negative value as the nFrame parameter disables automatic
|
|
checkpoints entirely.</p>
|
|
|
|
<p>The callback registered by this function replaces any existing callback
|
|
registered using <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a>. Likewise, registering a callback
|
|
using <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> disables the automatic checkpoint mechanism
|
|
configured by this function.</p>
|
|
|
|
<p>The <a href="pragma.html#pragma_wal_autocheckpoint">wal_autocheckpoint pragma</a> can be used to invoke this interface
|
|
from SQL.</p>
|
|
|
|
<p>Checkpoints initiated by this mechanism are
|
|
<a href="#sqlite3_wal_checkpoint_v2">PASSIVE</a>.</p>
|
|
|
|
<p>Every new <a href="#sqlite3">database connection</a> defaults to having the auto-checkpoint
|
|
enabled with a threshold of 1000 or <a href="compile.html#default_wal_autocheckpoint">SQLITE_DEFAULT_WAL_AUTOCHECKPOINT</a>
|
|
pages. The use of this interface
|
|
is only necessary if the default setting is found to be suboptimal
|
|
for a particular application.
|
|
</p><hr><a name="sqlite3_wal_checkpoint"></a>
|
|
<h2>Checkpoint a database</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_wal_checkpoint(D,X) is equivalent to
|
|
<a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2</a>(D,X,<a href="#SQLITE_CHECKPOINT_FULL">SQLITE_CHECKPOINT_PASSIVE</a>,0,0).</p>
|
|
|
|
<p>In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
|
|
<a href="wal.html">write-ahead log</a> for database X on <a href="#sqlite3">database connection</a> D to be
|
|
transferred into the database file and for the write-ahead log to
|
|
be reset. See the <a href="wal.html#ckpt">checkpointing</a> documentation for addition
|
|
information.</p>
|
|
|
|
<p>This interface used to be the only way to cause a checkpoint to
|
|
occur. But then the newer and more powerful <a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2()</a>
|
|
interface was added. This interface is retained for backwards
|
|
compatibility and as a convenience for applications that need to manually
|
|
start a callback but which do not need the full power (and corresponding
|
|
complication) of <a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2()</a>.
|
|
</p><hr><a name="sqlite3_wal_checkpoint_v2"></a>
|
|
<h2>Checkpoint a database</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_wal_checkpoint_v2(
|
|
sqlite3 *db, /* Database handle */
|
|
const char *zDb, /* Name of attached database (or NULL) */
|
|
int eMode, /* SQLITE_CHECKPOINT_* value */
|
|
int *pnLog, /* OUT: Size of WAL log in frames */
|
|
int *pnCkpt /* OUT: Total number of frames checkpointed */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
|
|
operation on database X of <a href="#sqlite3">database connection</a> D in mode M. Status
|
|
information is written back into integers pointed to by L and C.
|
|
The M parameter must be a valid <a href="#SQLITE_CHECKPOINT_FULL">checkpoint mode</a>:</p>
|
|
|
|
<p><dl>
|
|
<dt>SQLITE_CHECKPOINT_PASSIVE<dd>
|
|
Checkpoint as many frames as possible without waiting for any database
|
|
readers or writers to finish, then sync the database file if all frames
|
|
in the log were checkpointed. The <a href="#sqlite3_busy_handler">busy-handler callback</a>
|
|
is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
|
|
On the other hand, passive mode might leave the checkpoint unfinished
|
|
if there are concurrent readers or writers.</p>
|
|
|
|
<p><dt>SQLITE_CHECKPOINT_FULL<dd>
|
|
This mode blocks (it invokes the
|
|
<a href="#sqlite3_busy_handler">busy-handler callback</a>) until there is no
|
|
database writer and all readers are reading from the most recent database
|
|
snapshot. It then checkpoints all frames in the log file and syncs the
|
|
database file. This mode blocks new database writers while it is pending,
|
|
but new database readers are allowed to continue unimpeded.</p>
|
|
|
|
<p><dt>SQLITE_CHECKPOINT_RESTART<dd>
|
|
This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
|
|
that after checkpointing the log file it blocks (calls the
|
|
<a href="#sqlite3_busy_handler">busy-handler callback</a>)
|
|
until all readers are reading from the database file only. This ensures
|
|
that the next writer will restart the log file from the beginning.
|
|
Like SQLITE_CHECKPOINT_FULL, this mode blocks new
|
|
database writer attempts while it is pending, but does not impede readers.</p>
|
|
|
|
<p><dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
|
|
This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
|
|
addition that it also truncates the log file to zero bytes just prior
|
|
to a successful return.
|
|
</dl></p>
|
|
|
|
<p>If pnLog is not NULL, then *pnLog is set to the total number of frames in
|
|
the log file or to -1 if the checkpoint could not run because
|
|
of an error or because the database is not in <a href="wal.html">WAL mode</a>. If pnCkpt is not
|
|
NULL,then *pnCkpt is set to the total number of checkpointed frames in the
|
|
log file (including any that were already checkpointed before the function
|
|
was called) or to -1 if the checkpoint could not run due to an error or
|
|
because the database is not in WAL mode. Note that upon successful
|
|
completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
|
|
truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.</p>
|
|
|
|
<p>All calls obtain an exclusive "checkpoint" lock on the database file. If
|
|
any other process is running a checkpoint operation at the same time, the
|
|
lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a
|
|
busy-handler configured, it will not be invoked in this case.</p>
|
|
|
|
<p>The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
|
|
exclusive "writer" lock on the database file. If the writer lock cannot be
|
|
obtained immediately, and a busy-handler is configured, it is invoked and
|
|
the writer lock retried until either the busy-handler returns 0 or the lock
|
|
is successfully obtained. The busy-handler is also invoked while waiting for
|
|
database readers as described above. If the busy-handler returns 0 before
|
|
the writer lock is obtained or while waiting for database readers, the
|
|
checkpoint operation proceeds from that point in the same way as
|
|
SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
|
|
without blocking any further. SQLITE_BUSY is returned in this case.</p>
|
|
|
|
<p>If parameter zDb is NULL or points to a zero length string, then the
|
|
specified operation is attempted on all WAL databases <a href="lang_attach.html">attached</a> to
|
|
<a href="#sqlite3">database connection</a> db. In this case the
|
|
values written to output parameters *pnLog and *pnCkpt are undefined. If
|
|
an SQLITE_BUSY error is encountered when processing one or more of the
|
|
attached WAL databases, the operation is still attempted on any remaining
|
|
attached databases and SQLITE_BUSY is returned at the end. If any other
|
|
error occurs while processing an attached database, processing is abandoned
|
|
and the error code is returned to the caller immediately. If no error
|
|
(SQLITE_BUSY or otherwise) is encountered while processing the attached
|
|
databases, SQLITE_OK is returned.</p>
|
|
|
|
<p>If database zDb is the name of an attached database that is not in WAL
|
|
mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If
|
|
zDb is not NULL (or a zero length string) and is not the name of any
|
|
attached database, SQLITE_ERROR is returned to the caller.</p>
|
|
|
|
<p>Unless it returns SQLITE_MISUSE,
|
|
the sqlite3_wal_checkpoint_v2() interface
|
|
sets the error information that is queried by
|
|
<a href="#sqlite3_errcode">sqlite3_errcode()</a> and <a href="#sqlite3_errcode">sqlite3_errmsg()</a>.</p>
|
|
|
|
<p>The <a href="pragma.html#pragma_wal_checkpoint">PRAGMA wal_checkpoint</a> command can be used to invoke this interface
|
|
from SQL.
|
|
</p><hr><a name="sqlite3_wal_hook"></a>
|
|
<h2>Write-Ahead Log Commit Hook</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void *sqlite3_wal_hook(
|
|
sqlite3*,
|
|
int(*)(void *,sqlite3*,const char*,int),
|
|
void*
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> function is used to register a callback that
|
|
is invoked each time data is committed to a database in wal mode.</p>
|
|
|
|
<p>The callback is invoked by SQLite after the commit has taken place and
|
|
the associated write-lock on the database released, so the implementation
|
|
may read, write or <a href="wal.html#ckpt">checkpoint</a> the database as required.</p>
|
|
|
|
<p>The first parameter passed to the callback function when it is invoked
|
|
is a copy of the third parameter passed to sqlite3_wal_hook() when
|
|
registering the callback. The second is a copy of the database handle.
|
|
The third parameter is the name of the database that was written to -
|
|
either "main" or the name of an <a href="lang_attach.html">ATTACH</a>-ed database. The fourth parameter
|
|
is the number of pages currently in the write-ahead log file,
|
|
including those that were just committed.</p>
|
|
|
|
<p>The callback function should normally return <a href="#SQLITE_ABORT">SQLITE_OK</a>. If an error
|
|
code is returned, that error will propagate back up through the
|
|
SQLite code base to cause the statement that provoked the callback
|
|
to report an error, though the commit will have still occurred. If the
|
|
callback returns <a href="#SQLITE_ABORT">SQLITE_ROW</a> or <a href="#SQLITE_ABORT">SQLITE_DONE</a>, or if it returns a value
|
|
that does not correspond to any valid SQLite error code, the results
|
|
are undefined.</p>
|
|
|
|
<p>A single database handle may have at most a single write-ahead log callback
|
|
registered at one time. Calling <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> replaces any
|
|
previously registered write-ahead log callback. Note that the
|
|
<a href="#sqlite3_wal_autocheckpoint">sqlite3_wal_autocheckpoint()</a> interface and the
|
|
<a href="pragma.html#pragma_wal_autocheckpoint">wal_autocheckpoint pragma</a> both invoke <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> and will
|
|
overwrite any prior <a href="#sqlite3_wal_hook">sqlite3_wal_hook()</a> settings.
|
|
</p><hr><a name="sqlite3_snapshot"></a>
|
|
<h2>Database Snapshot</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_snapshot {
|
|
unsigned char hidden[48];
|
|
} sqlite3_snapshot;
|
|
</pre></blockquote>
|
|
<p>
|
|
An instance of the snapshot object records the state of a <a href="wal.html">WAL mode</a>
|
|
database for some specific point in history.</p>
|
|
|
|
<p>In <a href="wal.html">WAL mode</a>, multiple <a href="#sqlite3">database connections</a> that are open on the
|
|
same database file can each be reading a different historical version
|
|
of the database file. When a <a href="#sqlite3">database connection</a> begins a read
|
|
transaction, that connection sees an unchanging copy of the database
|
|
as it existed for the point in time when the transaction first started.
|
|
Subsequent changes to the database from other connections are not seen
|
|
by the reader until a new read transaction is started.</p>
|
|
|
|
<p>The sqlite3_snapshot object records state information about an historical
|
|
version of the database file so that it is possible to later open a new read
|
|
transaction that sees that historical version of the database rather than
|
|
the most recent version.
|
|
</p><p>Constructor: <a href="#sqlite3_snapshot_get">sqlite3_snapshot_get()</a></p>
|
|
<p>Destructor: <a href="#sqlite3_snapshot_free">sqlite3_snapshot_free()</a></p>
|
|
<p>Methods:
|
|
<a href="#sqlite3_snapshot_cmp">sqlite3_snapshot_cmp()</a>,
|
|
<a href="#sqlite3_snapshot_open">sqlite3_snapshot_open()</a>,
|
|
<a href="#sqlite3_snapshot_recover">sqlite3_snapshot_recover()</a></p>
|
|
<hr><a name="SQLITE_ABORT"></a>
|
|
<h2>Result Codes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_OK 0 /* Successful result */
|
|
/* beginning-of-error-codes */
|
|
#define SQLITE_ERROR 1 /* Generic error */
|
|
#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */
|
|
#define SQLITE_PERM 3 /* Access permission denied */
|
|
#define SQLITE_ABORT 4 /* Callback routine requested an abort */
|
|
#define SQLITE_BUSY 5 /* The database file is locked */
|
|
#define SQLITE_LOCKED 6 /* A table in the database is locked */
|
|
#define SQLITE_NOMEM 7 /* A malloc() failed */
|
|
#define SQLITE_READONLY 8 /* Attempt to write a readonly database */
|
|
#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/
|
|
#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */
|
|
#define SQLITE_CORRUPT 11 /* The database disk image is malformed */
|
|
#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */
|
|
#define SQLITE_FULL 13 /* Insertion failed because database is full */
|
|
#define SQLITE_CANTOPEN 14 /* Unable to open the database file */
|
|
#define SQLITE_PROTOCOL 15 /* Database lock protocol error */
|
|
#define SQLITE_EMPTY 16 /* Internal use only */
|
|
#define SQLITE_SCHEMA 17 /* The database schema changed */
|
|
#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */
|
|
#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */
|
|
#define SQLITE_MISMATCH 20 /* Data type mismatch */
|
|
#define SQLITE_MISUSE 21 /* Library used incorrectly */
|
|
#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */
|
|
#define SQLITE_AUTH 23 /* Authorization denied */
|
|
#define SQLITE_FORMAT 24 /* Not used */
|
|
#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */
|
|
#define SQLITE_NOTADB 26 /* File opened that is not a database file */
|
|
#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */
|
|
#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */
|
|
#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */
|
|
#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */
|
|
/* end-of-error-codes */
|
|
</pre></blockquote>
|
|
<p>
|
|
Many SQLite functions return an integer result code from the set shown
|
|
here in order to indicate success or failure.</p>
|
|
|
|
<p>New error codes may be added in future versions of SQLite.</p>
|
|
|
|
<p>See also: <a href="#SQLITE_ABORT_ROLLBACK">extended result code definitions</a>
|
|
</p><hr><a name="SQLITE_ABORT_ROLLBACK"></a>
|
|
<h2>Extended Result Codes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8))
|
|
#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8))
|
|
#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8))
|
|
#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8))
|
|
#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8))
|
|
#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8))
|
|
#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8))
|
|
#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8))
|
|
#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8))
|
|
#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8))
|
|
#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8))
|
|
#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8))
|
|
#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8))
|
|
#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8))
|
|
#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8))
|
|
#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8))
|
|
#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
|
|
#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8))
|
|
#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8))
|
|
#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8))
|
|
#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8))
|
|
#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8))
|
|
#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8))
|
|
#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8))
|
|
#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8))
|
|
#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8))
|
|
#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8))
|
|
#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8))
|
|
#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8))
|
|
#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8))
|
|
#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8))
|
|
#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8))
|
|
#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8))
|
|
#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8))
|
|
#define SQLITE_IOERR_DATA (SQLITE_IOERR | (32<<8))
|
|
#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8))
|
|
#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8))
|
|
#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8))
|
|
#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8))
|
|
#define SQLITE_BUSY_TIMEOUT (SQLITE_BUSY | (3<<8))
|
|
#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8))
|
|
#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8))
|
|
#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8))
|
|
#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8))
|
|
#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
|
|
#define SQLITE_CANTOPEN_SYMLINK (SQLITE_CANTOPEN | (6<<8))
|
|
#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8))
|
|
#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8))
|
|
#define SQLITE_CORRUPT_INDEX (SQLITE_CORRUPT | (3<<8))
|
|
#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8))
|
|
#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8))
|
|
#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8))
|
|
#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8))
|
|
#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8))
|
|
#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8))
|
|
#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8))
|
|
#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8))
|
|
#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8))
|
|
#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8))
|
|
#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8))
|
|
#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8))
|
|
#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8))
|
|
#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8))
|
|
#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8))
|
|
#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8))
|
|
#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8))
|
|
#define SQLITE_CONSTRAINT_PINNED (SQLITE_CONSTRAINT |(11<<8))
|
|
#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8))
|
|
#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
|
|
#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8))
|
|
#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8))
|
|
#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8))
|
|
#define SQLITE_OK_SYMLINK (SQLITE_OK | (2<<8))
|
|
</pre></blockquote>
|
|
<p>
|
|
In its default configuration, SQLite API routines return one of 30 integer
|
|
<a href="rescode.html">result codes</a>. However, experience has shown that many of
|
|
these result codes are too coarse-grained. They do not provide as
|
|
much information about problems as programmers might like. In an effort to
|
|
address this, newer versions of SQLite (version 3.3.8 2006-10-09
|
|
and later) include
|
|
support for additional result codes that provide more detailed information
|
|
about errors. These <a href="rescode.html#extrc">extended result codes</a> are enabled or disabled
|
|
on a per database connection basis using the
|
|
<a href="#sqlite3_extended_result_codes">sqlite3_extended_result_codes()</a> API. Or, the extended code for
|
|
the most recent error can be obtained using
|
|
<a href="#sqlite3_errcode">sqlite3_extended_errcode()</a>.
|
|
</p><hr><a name="SQLITE_ACCESS_EXISTS"></a>
|
|
<h2>Flags for the xAccess VFS method</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_ACCESS_EXISTS 0
|
|
#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */
|
|
#define SQLITE_ACCESS_READ 2 /* Unused */
|
|
</pre></blockquote>
|
|
<p>
|
|
These integer constants can be used as the third parameter to
|
|
the xAccess method of an <a href="#sqlite3_vfs">sqlite3_vfs</a> object. They determine
|
|
what kind of permissions the xAccess method is looking for.
|
|
With SQLITE_ACCESS_EXISTS, the xAccess method
|
|
simply checks whether the file exists.
|
|
With SQLITE_ACCESS_READWRITE, the xAccess method
|
|
checks whether the named directory is both readable and writable
|
|
(in other words, if files can be added, removed, and renamed within
|
|
the directory).
|
|
The SQLITE_ACCESS_READWRITE constant is currently used only by the
|
|
<a href="pragma.html#pragma_temp_store_directory">temp_store_directory pragma</a>, though this could change in a future
|
|
release of SQLite.
|
|
With SQLITE_ACCESS_READ, the xAccess method
|
|
checks whether the file is readable. The SQLITE_ACCESS_READ constant is
|
|
currently unused, though it might be used in a future release of
|
|
SQLite.
|
|
</p><hr><a name="SQLITE_ALTER_TABLE"></a>
|
|
<h2>Authorizer Action Codes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
/******************************************* 3rd ************ 4th ***********/
|
|
#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */
|
|
#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */
|
|
#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */
|
|
#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */
|
|
#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */
|
|
#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */
|
|
#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */
|
|
#define SQLITE_CREATE_VIEW 8 /* View Name NULL */
|
|
#define SQLITE_DELETE 9 /* Table Name NULL */
|
|
#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */
|
|
#define SQLITE_DROP_TABLE 11 /* Table Name NULL */
|
|
#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */
|
|
#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */
|
|
#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */
|
|
#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */
|
|
#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */
|
|
#define SQLITE_DROP_VIEW 17 /* View Name NULL */
|
|
#define SQLITE_INSERT 18 /* Table Name NULL */
|
|
#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */
|
|
#define SQLITE_READ 20 /* Table Name Column Name */
|
|
#define SQLITE_SELECT 21 /* NULL NULL */
|
|
#define SQLITE_TRANSACTION 22 /* Operation NULL */
|
|
#define SQLITE_UPDATE 23 /* Table Name Column Name */
|
|
#define SQLITE_ATTACH 24 /* Filename NULL */
|
|
#define SQLITE_DETACH 25 /* Database Name NULL */
|
|
#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */
|
|
#define SQLITE_REINDEX 27 /* Index Name NULL */
|
|
#define SQLITE_ANALYZE 28 /* Table Name NULL */
|
|
#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */
|
|
#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */
|
|
#define SQLITE_FUNCTION 31 /* NULL Function Name */
|
|
#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */
|
|
#define SQLITE_COPY 0 /* No longer used */
|
|
#define SQLITE_RECURSIVE 33 /* NULL NULL */
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_set_authorizer">sqlite3_set_authorizer()</a> interface registers a callback function
|
|
that is invoked to authorize certain SQL statement actions. The
|
|
second parameter to the callback is an integer code that specifies
|
|
what action is being authorized. These are the integer action codes that
|
|
the authorizer callback may be passed.</p>
|
|
|
|
<p>These action code values signify what kind of operation is to be
|
|
authorized. The 3rd and 4th parameters to the authorization
|
|
callback function will be parameters or NULL depending on which of these
|
|
codes is used as the second parameter. The 5th parameter to the
|
|
authorizer callback is the name of the database ("main", "temp",
|
|
etc.) if applicable. The 6th parameter to the authorizer callback
|
|
is the name of the inner-most trigger or view that is responsible for
|
|
the access attempt or NULL if this access attempt is directly from
|
|
top-level SQL code.
|
|
</p><hr><a name="SQLITE_ANY"></a>
|
|
<h2>Text Encodings</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */
|
|
#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */
|
|
#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */
|
|
#define SQLITE_UTF16 4 /* Use native byte order */
|
|
#define SQLITE_ANY 5 /* Deprecated */
|
|
#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */
|
|
</pre></blockquote>
|
|
<p>
|
|
These constant define integer codes that represent the various
|
|
text encodings supported by SQLite.
|
|
</p><hr><a name="SQLITE_BLOB"></a>
|
|
<h2>Fundamental Datatypes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_INTEGER 1
|
|
#define SQLITE_FLOAT 2
|
|
#define SQLITE_BLOB 4
|
|
#define SQLITE_NULL 5
|
|
#ifdef SQLITE_TEXT
|
|
# undef SQLITE_TEXT
|
|
#else
|
|
# define SQLITE_TEXT 3
|
|
#endif
|
|
#define SQLITE3_TEXT 3
|
|
</pre></blockquote>
|
|
<p>
|
|
Every value in SQLite has one of five fundamental datatypes:</p>
|
|
|
|
<p><ul>
|
|
<li> 64-bit signed integer
|
|
<li> 64-bit IEEE floating point number
|
|
<li> string
|
|
<li> BLOB
|
|
<li> NULL
|
|
</ul></p>
|
|
|
|
<p>These constants are codes for each of those types.</p>
|
|
|
|
<p>Note that the SQLITE_TEXT constant was also used in SQLite version 2
|
|
for a completely different meaning. Software that links against both
|
|
SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
|
|
SQLITE_TEXT.
|
|
</p><hr><a name="SQLITE_CHECKPOINT_FULL"></a>
|
|
<h2>Checkpoint Mode Values</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */
|
|
#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */
|
|
#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */
|
|
#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants define all valid values for the "checkpoint mode" passed
|
|
as the third parameter to the <a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2()</a> interface.
|
|
See the <a href="#sqlite3_wal_checkpoint_v2">sqlite3_wal_checkpoint_v2()</a> documentation for details on the
|
|
meaning of each of these checkpoint modes.
|
|
</p><hr><a name="SQLITE_CONFIG_COVERING_INDEX_SCAN"></a>
|
|
<h2>Configuration Options</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */
|
|
#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */
|
|
#define SQLITE_CONFIG_SERIALIZED 3 /* nil */
|
|
#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */
|
|
#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */
|
|
#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */
|
|
#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */
|
|
#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */
|
|
#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */
|
|
#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */
|
|
#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */
|
|
/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */
|
|
#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */
|
|
#define SQLITE_CONFIG_PCACHE 14 /* no-op */
|
|
#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */
|
|
#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */
|
|
#define SQLITE_CONFIG_URI 17 /* int */
|
|
#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */
|
|
#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */
|
|
#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */
|
|
#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */
|
|
#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */
|
|
#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */
|
|
#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */
|
|
#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */
|
|
#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */
|
|
#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */
|
|
#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */
|
|
#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants are the available integer configuration options that
|
|
can be passed as the first argument to the <a href="#sqlite3_config">sqlite3_config()</a> interface.</p>
|
|
|
|
<p>New configuration options may be added in future releases of SQLite.
|
|
Existing configuration options might be discontinued. Applications
|
|
should check the return code from <a href="#sqlite3_config">sqlite3_config()</a> to make sure that
|
|
the call worked. The <a href="#sqlite3_config">sqlite3_config()</a> interface will return a
|
|
non-zero <a href="rescode.html">error code</a> if a discontinued or unsupported configuration option
|
|
is invoked.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqliteconfigsinglethread"></a>
|
|
<dt>SQLITE_CONFIG_SINGLETHREAD</dt>
|
|
<dd>There are no arguments to this option. This option sets the
|
|
<a href="threadsafe.html">threading mode</a> to Single-thread. In other words, it disables
|
|
all mutexing and puts SQLite into a mode where it can only be used
|
|
by a single thread. If SQLite is compiled with
|
|
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
it is not possible to change the <a href="threadsafe.html">threading mode</a> from its default
|
|
value of Single-thread and so <a href="#sqlite3_config">sqlite3_config()</a> will return
|
|
<a href="#SQLITE_ABORT">SQLITE_ERROR</a> if called with the SQLITE_CONFIG_SINGLETHREAD
|
|
configuration option.</dd></p>
|
|
|
|
<p><a name="sqliteconfigmultithread"></a>
|
|
<dt>SQLITE_CONFIG_MULTITHREAD</dt>
|
|
<dd>There are no arguments to this option. This option sets the
|
|
<a href="threadsafe.html">threading mode</a> to Multi-thread. In other words, it disables
|
|
mutexing on <a href="#sqlite3">database connection</a> and <a href="#sqlite3_stmt">prepared statement</a> objects.
|
|
The application is responsible for serializing access to
|
|
<a href="#sqlite3">database connections</a> and <a href="#sqlite3_stmt">prepared statements</a>. But other mutexes
|
|
are enabled so that SQLite will be safe to use in a multi-threaded
|
|
environment as long as no two threads attempt to use the same
|
|
<a href="#sqlite3">database connection</a> at the same time. If SQLite is compiled with
|
|
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
it is not possible to set the Multi-thread <a href="threadsafe.html">threading mode</a> and
|
|
<a href="#sqlite3_config">sqlite3_config()</a> will return <a href="#SQLITE_ABORT">SQLITE_ERROR</a> if called with the
|
|
SQLITE_CONFIG_MULTITHREAD configuration option.</dd></p>
|
|
|
|
<p><a name="sqliteconfigserialized"></a>
|
|
<dt>SQLITE_CONFIG_SERIALIZED</dt>
|
|
<dd>There are no arguments to this option. This option sets the
|
|
<a href="threadsafe.html">threading mode</a> to Serialized. In other words, this option enables
|
|
all mutexes including the recursive
|
|
mutexes on <a href="#sqlite3">database connection</a> and <a href="#sqlite3_stmt">prepared statement</a> objects.
|
|
In this mode (which is the default when SQLite is compiled with
|
|
<a href="compile.html#threadsafe">SQLITE_THREADSAFE=1</a>) the SQLite library will itself serialize access
|
|
to <a href="#sqlite3">database connections</a> and <a href="#sqlite3_stmt">prepared statements</a> so that the
|
|
application is free to use the same <a href="#sqlite3">database connection</a> or the
|
|
same <a href="#sqlite3_stmt">prepared statement</a> in different threads at the same time.
|
|
If SQLite is compiled with
|
|
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
it is not possible to set the Serialized <a href="threadsafe.html">threading mode</a> and
|
|
<a href="#sqlite3_config">sqlite3_config()</a> will return <a href="#SQLITE_ABORT">SQLITE_ERROR</a> if called with the
|
|
SQLITE_CONFIG_SERIALIZED configuration option.</dd></p>
|
|
|
|
<p><a name="sqliteconfigmalloc"></a>
|
|
<dt>SQLITE_CONFIG_MALLOC</dt>
|
|
<dd> The SQLITE_CONFIG_MALLOC option takes a single argument which is
|
|
a pointer to an instance of the <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a> structure.
|
|
The argument specifies
|
|
alternative low-level memory allocation routines to be used in place of
|
|
the memory allocation routines built into SQLite. SQLite makes
|
|
its own private copy of the content of the <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a> structure
|
|
before the <a href="#sqlite3_config">sqlite3_config()</a> call returns.</dd></p>
|
|
|
|
<p><a name="sqliteconfiggetmalloc"></a>
|
|
<dt>SQLITE_CONFIG_GETMALLOC</dt>
|
|
<dd> The SQLITE_CONFIG_GETMALLOC option takes a single argument which
|
|
is a pointer to an instance of the <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a> structure.
|
|
The <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a>
|
|
structure is filled with the currently defined memory allocation routines.
|
|
This option can be used to overload the default memory allocation
|
|
routines with a wrapper that simulations memory allocation failure or
|
|
tracks memory usage, for example. </dd></p>
|
|
|
|
<p><a name="sqliteconfigsmallmalloc"></a>
|
|
<dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
|
|
<dd> The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
|
|
type int, interpreted as a boolean, which if true provides a hint to
|
|
SQLite that it should avoid large memory allocations if possible.
|
|
SQLite will run faster if it is free to make large memory allocations,
|
|
but some application might prefer to run slower in exchange for
|
|
guarantees about memory fragmentation that are possible if large
|
|
allocations are avoided. This hint is normally off.
|
|
</dd></p>
|
|
|
|
<p><a name="sqliteconfigmemstatus"></a>
|
|
<dt>SQLITE_CONFIG_MEMSTATUS</dt>
|
|
<dd> The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
|
|
interpreted as a boolean, which enables or disables the collection of
|
|
memory allocation statistics. When memory allocation statistics are
|
|
disabled, the following SQLite interfaces become non-operational:
|
|
<ul>
|
|
<li> <a href="#sqlite3_hard_heap_limit64">sqlite3_hard_heap_limit64()</a>
|
|
<li> <a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a>
|
|
<li> <a href="#sqlite3_memory_highwater">sqlite3_memory_highwater()</a>
|
|
<li> <a href="#sqlite3_hard_heap_limit64">sqlite3_soft_heap_limit64()</a>
|
|
<li> <a href="#sqlite3_status">sqlite3_status64()</a>
|
|
</ul>
|
|
Memory allocation statistics are enabled by default unless SQLite is
|
|
compiled with <a href="compile.html#default_memstatus">SQLITE_DEFAULT_MEMSTATUS</a>=0 in which case memory
|
|
allocation statistics are disabled by default.
|
|
</dd></p>
|
|
|
|
<p><a name="sqliteconfigscratch"></a>
|
|
<dt>SQLITE_CONFIG_SCRATCH</dt>
|
|
<dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
|
|
</dd></p>
|
|
|
|
<p><a name="sqliteconfigpagecache"></a>
|
|
<dt>SQLITE_CONFIG_PAGECACHE</dt>
|
|
<dd> The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
|
|
that SQLite can use for the database page cache with the default page
|
|
cache implementation.
|
|
This configuration option is a no-op if an application-defined page
|
|
cache implementation is loaded using the <a href="#sqliteconfigpcache2">SQLITE_CONFIG_PCACHE2</a>.
|
|
There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
|
|
8-byte aligned memory (pMem), the size of each page cache line (sz),
|
|
and the number of cache lines (N).
|
|
The sz argument should be the size of the largest database page
|
|
(a power of two between 512 and 65536) plus some extra bytes for each
|
|
page header. The number of extra bytes needed by the page header
|
|
can be determined using <a href="#sqliteconfigpcachehdrsz">SQLITE_CONFIG_PCACHE_HDRSZ</a>.
|
|
It is harmless, apart from the wasted memory,
|
|
for the sz parameter to be larger than necessary. The pMem
|
|
argument must be either a NULL pointer or a pointer to an 8-byte
|
|
aligned block of memory of at least sz*N bytes, otherwise
|
|
subsequent behavior is undefined.
|
|
When pMem is not NULL, SQLite will strive to use the memory provided
|
|
to satisfy page cache needs, falling back to <a href="#sqlite3_free">sqlite3_malloc()</a> if
|
|
a page cache line is larger than sz bytes or if all of the pMem buffer
|
|
is exhausted.
|
|
If pMem is NULL and N is non-zero, then each database connection
|
|
does an initial bulk allocation for page cache memory
|
|
from <a href="#sqlite3_free">sqlite3_malloc()</a> sufficient for N cache lines if N is positive or
|
|
of -1024*N bytes if N is negative, . If additional
|
|
page cache memory is needed beyond what is provided by the initial
|
|
allocation, then SQLite goes to <a href="#sqlite3_free">sqlite3_malloc()</a> separately for each
|
|
additional cache line. </dd></p>
|
|
|
|
<p><a name="sqliteconfigheap"></a>
|
|
<dt>SQLITE_CONFIG_HEAP</dt>
|
|
<dd> The SQLITE_CONFIG_HEAP option specifies a static memory buffer
|
|
that SQLite will use for all of its dynamic memory allocation needs
|
|
beyond those provided for by <a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>.
|
|
The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
|
|
with either <a href="compile.html#enable_memsys3">SQLITE_ENABLE_MEMSYS3</a> or <a href="compile.html#enable_memsys5">SQLITE_ENABLE_MEMSYS5</a> and returns
|
|
<a href="#SQLITE_ABORT">SQLITE_ERROR</a> if invoked otherwise.
|
|
There are three arguments to SQLITE_CONFIG_HEAP:
|
|
An 8-byte aligned pointer to the memory,
|
|
the number of bytes in the memory buffer, and the minimum allocation size.
|
|
If the first pointer (the memory pointer) is NULL, then SQLite reverts
|
|
to using its default memory allocator (the system malloc() implementation),
|
|
undoing any prior invocation of <a href="#sqliteconfigmalloc">SQLITE_CONFIG_MALLOC</a>. If the
|
|
memory pointer is not NULL then the alternative memory
|
|
allocator is engaged to handle all of SQLites memory allocation needs.
|
|
The first pointer (the memory pointer) must be aligned to an 8-byte
|
|
boundary or subsequent behavior of SQLite will be undefined.
|
|
The minimum allocation size is capped at 2**12. Reasonable values
|
|
for the minimum allocation size are 2**5 through 2**8.</dd></p>
|
|
|
|
<p><a name="sqliteconfigmutex"></a>
|
|
<dt>SQLITE_CONFIG_MUTEX</dt>
|
|
<dd> The SQLITE_CONFIG_MUTEX option takes a single argument which is a
|
|
pointer to an instance of the <a href="#sqlite3_mutex_methods">sqlite3_mutex_methods</a> structure.
|
|
The argument specifies alternative low-level mutex routines to be used
|
|
in place the mutex routines built into SQLite. SQLite makes a copy of
|
|
the content of the <a href="#sqlite3_mutex_methods">sqlite3_mutex_methods</a> structure before the call to
|
|
<a href="#sqlite3_config">sqlite3_config()</a> returns. If SQLite is compiled with
|
|
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
the entire mutexing subsystem is omitted from the build and hence calls to
|
|
<a href="#sqlite3_config">sqlite3_config()</a> with the SQLITE_CONFIG_MUTEX configuration option will
|
|
return <a href="#SQLITE_ABORT">SQLITE_ERROR</a>.</dd></p>
|
|
|
|
<p><a name="sqliteconfiggetmutex"></a>
|
|
<dt>SQLITE_CONFIG_GETMUTEX</dt>
|
|
<dd> The SQLITE_CONFIG_GETMUTEX option takes a single argument which
|
|
is a pointer to an instance of the <a href="#sqlite3_mutex_methods">sqlite3_mutex_methods</a> structure. The
|
|
<a href="#sqlite3_mutex_methods">sqlite3_mutex_methods</a>
|
|
structure is filled with the currently defined mutex routines.
|
|
This option can be used to overload the default mutex allocation
|
|
routines with a wrapper used to track mutex usage for performance
|
|
profiling or testing, for example. If SQLite is compiled with
|
|
the <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> compile-time option then
|
|
the entire mutexing subsystem is omitted from the build and hence calls to
|
|
<a href="#sqlite3_config">sqlite3_config()</a> with the SQLITE_CONFIG_GETMUTEX configuration option will
|
|
return <a href="#SQLITE_ABORT">SQLITE_ERROR</a>.</dd></p>
|
|
|
|
<p><a name="sqliteconfiglookaside"></a>
|
|
<dt>SQLITE_CONFIG_LOOKASIDE</dt>
|
|
<dd> The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
|
|
the default size of lookaside memory on each <a href="#sqlite3">database connection</a>.
|
|
The first argument is the
|
|
size of each lookaside buffer slot and the second is the number of
|
|
slots allocated to each database connection. SQLITE_CONFIG_LOOKASIDE
|
|
sets the <i>default</i> lookaside size. The <a href="#sqlitedbconfiglookaside">SQLITE_DBCONFIG_LOOKASIDE</a>
|
|
option to <a href="#sqlite3_db_config">sqlite3_db_config()</a> can be used to change the lookaside
|
|
configuration on individual connections. </dd></p>
|
|
|
|
<p><a name="sqliteconfigpcache2"></a>
|
|
<dt>SQLITE_CONFIG_PCACHE2</dt>
|
|
<dd> The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
|
|
a pointer to an <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> object. This object specifies
|
|
the interface to a custom page cache implementation.
|
|
SQLite makes a copy of the <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> object.</dd></p>
|
|
|
|
<p><a name="sqliteconfiggetpcache2"></a>
|
|
<dt>SQLITE_CONFIG_GETPCACHE2</dt>
|
|
<dd> The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
|
|
is a pointer to an <a href="#sqlite3_pcache_methods2">sqlite3_pcache_methods2</a> object. SQLite copies of
|
|
the current page cache implementation into that object. </dd></p>
|
|
|
|
<p><a name="sqliteconfiglog"></a>
|
|
<dt>SQLITE_CONFIG_LOG</dt>
|
|
<dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
|
|
global <a href="errlog.html">error log</a>.
|
|
(The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
|
|
function with a call signature of void(*)(void*,int,const char*),
|
|
and a pointer to void. If the function pointer is not NULL, it is
|
|
invoked by <a href="#sqlite3_log">sqlite3_log()</a> to process each logging event. If the
|
|
function pointer is NULL, the <a href="#sqlite3_log">sqlite3_log()</a> interface becomes a no-op.
|
|
The void pointer that is the second argument to SQLITE_CONFIG_LOG is
|
|
passed through as the first parameter to the application-defined logger
|
|
function whenever that function is invoked. The second parameter to
|
|
the logger function is a copy of the first parameter to the corresponding
|
|
<a href="#sqlite3_log">sqlite3_log()</a> call and is intended to be a <a href="rescode.html">result code</a> or an
|
|
<a href="rescode.html#extrc">extended result code</a>. The third parameter passed to the logger is
|
|
log message after formatting via <a href="#sqlite3_mprintf">sqlite3_snprintf()</a>.
|
|
The SQLite logging interface is not reentrant; the logger function
|
|
supplied by the application must not invoke any SQLite interface.
|
|
In a multi-threaded application, the application-defined logger
|
|
function must be threadsafe. </dd></p>
|
|
|
|
<p><a name="sqliteconfiguri"></a>
|
|
<dt>SQLITE_CONFIG_URI
|
|
<dd>The SQLITE_CONFIG_URI option takes a single argument of type int.
|
|
If non-zero, then URI handling is globally enabled. If the parameter is zero,
|
|
then URI handling is globally disabled. If URI handling is globally
|
|
enabled, all filenames passed to <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open_v2()</a>,
|
|
<a href="#sqlite3_open">sqlite3_open16()</a> or
|
|
specified as part of <a href="lang_attach.html">ATTACH</a> commands are interpreted as URIs, regardless
|
|
of whether or not the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_URI</a> flag is set when the database
|
|
connection is opened. If it is globally disabled, filenames are
|
|
only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
|
|
database connection is opened. By default, URI handling is globally
|
|
disabled. The default value may be changed by compiling with the
|
|
<a href="compile.html#use_uri">SQLITE_USE_URI</a> symbol defined.</p>
|
|
|
|
<p><a name="sqliteconfigcoveringindexscan"></a>
|
|
<dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
|
|
<dd>The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
|
|
argument which is interpreted as a boolean in order to enable or disable
|
|
the use of covering indices for full table scans in the query optimizer.
|
|
The default setting is determined
|
|
by the <a href="compile.html#allow_covering_index_scan">SQLITE_ALLOW_COVERING_INDEX_SCAN</a> compile-time option, or is "on"
|
|
if that compile-time option is omitted.
|
|
The ability to disable the use of covering indices for full table scans
|
|
is because some incorrectly coded legacy applications might malfunction
|
|
when the optimization is enabled. Providing the ability to
|
|
disable the optimization allows the older, buggy application code to work
|
|
without change even with newer versions of SQLite.</p>
|
|
|
|
<p><a name="sqliteconfigpcache"></a>
|
|
<a name="sqliteconfiggetpcache"></a>
|
|
|
|
<dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
|
|
<dd> These options are obsolete and should not be used by new code.
|
|
They are retained for backwards compatibility but are now no-ops.
|
|
</dd></p>
|
|
|
|
<p><a name="sqliteconfigsqllog"></a>
|
|
|
|
<dt>SQLITE_CONFIG_SQLLOG
|
|
<dd>This option is only available if sqlite is compiled with the
|
|
<a href="compile.html#enable_sqllog">SQLITE_ENABLE_SQLLOG</a> pre-processor macro defined. The first argument should
|
|
be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
|
|
The second should be of type (void*). The callback is invoked by the library
|
|
in three separate circumstances, identified by the value passed as the
|
|
fourth parameter. If the fourth parameter is 0, then the database connection
|
|
passed as the second argument has just been opened. The third argument
|
|
points to a buffer containing the name of the main database file. If the
|
|
fourth parameter is 1, then the SQL statement that the third parameter
|
|
points to has just been executed. Or, if the fourth parameter is 2, then
|
|
the connection being passed as the second parameter is being closed. The
|
|
third parameter is passed NULL In this case. An example of using this
|
|
configuration option can be seen in the "test_sqllog.c" source file in
|
|
the canonical SQLite source tree.</dd></p>
|
|
|
|
<p><a name="sqliteconfigmmapsize"></a>
|
|
|
|
<dt>SQLITE_CONFIG_MMAP_SIZE
|
|
<dd>SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
|
|
that are the default mmap size limit (the default setting for
|
|
<a href="pragma.html#pragma_mmap_size">PRAGMA mmap_size</a>) and the maximum allowed mmap size limit.
|
|
The default setting can be overridden by each database connection using
|
|
either the <a href="pragma.html#pragma_mmap_size">PRAGMA mmap_size</a> command, or by using the
|
|
<a href="#sqlitefcntlmmapsize">SQLITE_FCNTL_MMAP_SIZE</a> file control. The maximum allowed mmap size
|
|
will be silently truncated if necessary so that it does not exceed the
|
|
compile-time maximum mmap size set by the
|
|
<a href="compile.html#max_mmap_size">SQLITE_MAX_MMAP_SIZE</a> compile-time option.
|
|
If either argument to this option is negative, then that argument is
|
|
changed to its compile-time default.</p>
|
|
|
|
<p><a name="sqliteconfigwin32heapsize"></a>
|
|
|
|
<dt>SQLITE_CONFIG_WIN32_HEAPSIZE
|
|
<dd>The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
|
|
compiled for Windows with the <a href="compile.html#win32_malloc">SQLITE_WIN32_MALLOC</a> pre-processor macro
|
|
defined. SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
|
|
that specifies the maximum size of the created heap.</p>
|
|
|
|
<p><a name="sqliteconfigpcachehdrsz"></a>
|
|
|
|
<dt>SQLITE_CONFIG_PCACHE_HDRSZ
|
|
<dd>The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
|
|
is a pointer to an integer and writes into that integer the number of extra
|
|
bytes per page required for each page in <a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>.
|
|
The amount of extra space required can change depending on the compiler,
|
|
target platform, and SQLite version.</p>
|
|
|
|
<p><a name="sqliteconfigpmasz"></a>
|
|
|
|
<dt>SQLITE_CONFIG_PMASZ
|
|
<dd>The SQLITE_CONFIG_PMASZ option takes a single parameter which
|
|
is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
|
|
sorter to that integer. The default minimum PMA Size is set by the
|
|
<a href="compile.html#sorter_pmasz">SQLITE_SORTER_PMASZ</a> compile-time option. New threads are launched
|
|
to help with sort operations when multithreaded sorting
|
|
is enabled (using the <a href="pragma.html#pragma_threads">PRAGMA threads</a> command) and the amount of content
|
|
to be sorted exceeds the page size times the minimum of the
|
|
<a href="pragma.html#pragma_cache_size">PRAGMA cache_size</a> setting and this value.</p>
|
|
|
|
<p><a name="sqliteconfigstmtjrnlspill"></a>
|
|
|
|
<dt>SQLITE_CONFIG_STMTJRNL_SPILL
|
|
<dd>The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
|
|
becomes the <a href="tempfiles.html#stmtjrnl">statement journal</a> spill-to-disk threshold.
|
|
<a href="tempfiles.html#stmtjrnl">Statement journals</a> are held in memory until their size (in bytes)
|
|
exceeds this threshold, at which point they are written to disk.
|
|
Or if the threshold is -1, statement journals are always held
|
|
exclusively in memory.
|
|
Since many statement journals never become large, setting the spill
|
|
threshold to a value such as 64KiB can greatly reduce the amount of
|
|
I/O required to support statement rollback.
|
|
The default value for this setting is controlled by the
|
|
<a href="compile.html#stmtjrnl_spill">SQLITE_STMTJRNL_SPILL</a> compile-time option.</p>
|
|
|
|
<p><a name="sqliteconfigsorterrefsize"></a>
|
|
|
|
<dt>SQLITE_CONFIG_SORTERREF_SIZE
|
|
<dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
|
|
of type (int) - the new value of the sorter-reference size threshold.
|
|
Usually, when SQLite uses an external sort to order records according
|
|
to an ORDER BY clause, all fields required by the caller are present in the
|
|
sorted records. However, if SQLite determines based on the declared type
|
|
of a table column that its values are likely to be very large - larger
|
|
than the configured sorter-reference size threshold - then a reference
|
|
is stored in each sorted record and the required column values loaded
|
|
from the database as records are returned in sorted order. The default
|
|
value for this option is to never use this optimization. Specifying a
|
|
negative value for this option restores the default behaviour.
|
|
This option is only available if SQLite is compiled with the
|
|
<a href="compile.html#enable_sorter_references">SQLITE_ENABLE_SORTER_REFERENCES</a> compile-time option.</p>
|
|
|
|
<p><a name="sqliteconfigmemdbmaxsize"></a>
|
|
|
|
<dt>SQLITE_CONFIG_MEMDB_MAXSIZE
|
|
<dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
|
|
<a href="#sqlite3_int64">sqlite3_int64</a> parameter which is the default maximum size for an in-memory
|
|
database created using <a href="#sqlite3_deserialize">sqlite3_deserialize()</a>. This default maximum
|
|
size can be adjusted up or down for individual databases using the
|
|
<a href="#sqlitefcntlsizelimit">SQLITE_FCNTL_SIZE_LIMIT</a> <a href="#sqlite3_file_control">file-control</a>. If this
|
|
configuration setting is never used, then the default maximum is determined
|
|
by the <a href="compile.html#memdb_default_maxsize">SQLITE_MEMDB_DEFAULT_MAXSIZE</a> compile-time option. If that
|
|
compile-time option is not set, then the default maximum is 1073741824.
|
|
</dl>
|
|
</p><hr><a name="SQLITE_DBCONFIG_DEFENSIVE"></a>
|
|
<h2>Database Connection Configuration Options</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */
|
|
#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */
|
|
#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */
|
|
#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */
|
|
#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
|
|
#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
|
|
#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */
|
|
#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */
|
|
#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */
|
|
#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */
|
|
#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */
|
|
#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */
|
|
#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */
|
|
#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */
|
|
#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */
|
|
#define SQLITE_DBCONFIG_ENABLE_VIEW 1015 /* int int* */
|
|
#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT 1016 /* int int* */
|
|
#define SQLITE_DBCONFIG_TRUSTED_SCHEMA 1017 /* int int* */
|
|
#define SQLITE_DBCONFIG_MAX 1017 /* Largest DBCONFIG */
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants are the available integer configuration options that
|
|
can be passed as the second argument to the <a href="#sqlite3_db_config">sqlite3_db_config()</a> interface.</p>
|
|
|
|
<p>New configuration options may be added in future releases of SQLite.
|
|
Existing configuration options might be discontinued. Applications
|
|
should check the return code from <a href="#sqlite3_db_config">sqlite3_db_config()</a> to make sure that
|
|
the call worked. The <a href="#sqlite3_db_config">sqlite3_db_config()</a> interface will return a
|
|
non-zero <a href="rescode.html">error code</a> if a discontinued or unsupported configuration option
|
|
is invoked.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitedbconfiglookaside"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
|
|
<dd> This option takes three additional arguments that determine the
|
|
<a href="malloc.html#lookaside">lookaside memory allocator</a> configuration for the <a href="#sqlite3">database connection</a>.
|
|
The first argument (the third parameter to <a href="#sqlite3_db_config">sqlite3_db_config()</a> is a
|
|
pointer to a memory buffer to use for lookaside memory.
|
|
The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
|
|
may be NULL in which case SQLite will allocate the
|
|
lookaside buffer itself using <a href="#sqlite3_free">sqlite3_malloc()</a>. The second argument is the
|
|
size of each lookaside buffer slot. The third argument is the number of
|
|
slots. The size of the buffer in the first argument must be greater than
|
|
or equal to the product of the second and third arguments. The buffer
|
|
must be aligned to an 8-byte boundary. If the second argument to
|
|
SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
|
|
rounded down to the next smaller multiple of 8. The lookaside memory
|
|
configuration for a database connection can only be changed when that
|
|
connection is not currently using lookaside memory, or in other words
|
|
when the "current value" returned by
|
|
<a href="#sqlite3_db_status">sqlite3_db_status</a>(D,<a href="#sqliteconfiglookaside">SQLITE_CONFIG_LOOKASIDE</a>,...) is zero.
|
|
Any attempt to change the lookaside memory configuration when lookaside
|
|
memory is in use leaves the configuration unchanged and returns
|
|
<a href="#SQLITE_ABORT">SQLITE_BUSY</a>.</dd></p>
|
|
|
|
<p><a name="sqlitedbconfigenablefkey"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
|
|
<dd> This option is used to enable or disable the enforcement of
|
|
<a href="foreignkeys.html">foreign key constraints</a>. There should be two additional arguments.
|
|
The first argument is an integer which is 0 to disable FK enforcement,
|
|
positive to enable FK enforcement or negative to leave FK enforcement
|
|
unchanged. The second parameter is a pointer to an integer into which
|
|
is written 0 or 1 to indicate whether FK enforcement is off or on
|
|
following this call. The second parameter may be a NULL pointer, in
|
|
which case the FK enforcement setting is not reported back. </dd></p>
|
|
|
|
<p><a name="sqlitedbconfigenabletrigger"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
|
|
<dd> This option is used to enable or disable <a href="lang_createtrigger.html">triggers</a>.
|
|
There should be two additional arguments.
|
|
The first argument is an integer which is 0 to disable triggers,
|
|
positive to enable triggers or negative to leave the setting unchanged.
|
|
The second parameter is a pointer to an integer into which
|
|
is written 0 or 1 to indicate whether triggers are disabled or enabled
|
|
following this call. The second parameter may be a NULL pointer, in
|
|
which case the trigger setting is not reported back. </dd></p>
|
|
|
|
<p><a name="sqlitedbconfigenableview"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
|
|
<dd> This option is used to enable or disable <a href="lang_createview.html">views</a>.
|
|
There should be two additional arguments.
|
|
The first argument is an integer which is 0 to disable views,
|
|
positive to enable views or negative to leave the setting unchanged.
|
|
The second parameter is a pointer to an integer into which
|
|
is written 0 or 1 to indicate whether views are disabled or enabled
|
|
following this call. The second parameter may be a NULL pointer, in
|
|
which case the view setting is not reported back. </dd></p>
|
|
|
|
<p><a name="sqlitedbconfigenablefts3tokenizer"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
|
|
<dd> This option is used to enable or disable the
|
|
<a href="fts3.html#f3tknzr">fts3_tokenizer()</a> function which is part of the
|
|
<a href="fts3.html">FTS3</a> full-text search engine extension.
|
|
There should be two additional arguments.
|
|
The first argument is an integer which is 0 to disable fts3_tokenizer() or
|
|
positive to enable fts3_tokenizer() or negative to leave the setting
|
|
unchanged.
|
|
The second parameter is a pointer to an integer into which
|
|
is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
|
|
following this call. The second parameter may be a NULL pointer, in
|
|
which case the new setting is not reported back. </dd></p>
|
|
|
|
<p><a name="sqlitedbconfigenableloadextension"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
|
|
<dd> This option is used to enable or disable the <a href="#sqlite3_load_extension">sqlite3_load_extension()</a>
|
|
interface independently of the <a href="lang_corefunc.html#load_extension">load_extension()</a> SQL function.
|
|
The <a href="#sqlite3_enable_load_extension">sqlite3_enable_load_extension()</a> API enables or disables both the
|
|
C-API <a href="#sqlite3_load_extension">sqlite3_load_extension()</a> and the SQL function <a href="lang_corefunc.html#load_extension">load_extension()</a>.
|
|
There should be two additional arguments.
|
|
When the first argument to this interface is 1, then only the C-API is
|
|
enabled and the SQL function remains disabled. If the first argument to
|
|
this interface is 0, then both the C-API and the SQL function are disabled.
|
|
If the first argument is -1, then no changes are made to state of either the
|
|
C-API or the SQL function.
|
|
The second parameter is a pointer to an integer into which
|
|
is written 0 or 1 to indicate whether <a href="#sqlite3_load_extension">sqlite3_load_extension()</a> interface
|
|
is disabled or enabled following this call. The second parameter may
|
|
be a NULL pointer, in which case the new setting is not reported back.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfigmaindbname"></a>
|
|
<dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
|
|
<dd> This option is used to change the name of the "main" database
|
|
schema. The sole argument is a pointer to a constant UTF8 string
|
|
which will become the new schema name in place of "main". SQLite
|
|
does not make a copy of the new main schema name string, so the application
|
|
must ensure that the argument passed into this DBCONFIG option is unchanged
|
|
until after the database connection closes.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfignockptonclose"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
|
|
<dd> Usually, when a database in wal mode is closed or detached from a
|
|
database handle, SQLite checks if this will mean that there are now no
|
|
connections at all to the database. If so, it performs a checkpoint
|
|
operation before closing the connection. This option may be used to
|
|
override this behaviour. The first parameter passed to this operation
|
|
is an integer - positive to disable checkpoints-on-close, or zero (the
|
|
default) to enable them, and negative to leave the setting unchanged.
|
|
The second parameter is a pointer to an integer
|
|
into which is written 0 or 1 to indicate whether checkpoints-on-close
|
|
have been disabled - 0 if they are not disabled, 1 if they are.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfigenableqpsg"></a>
|
|
<dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
|
|
<dd>The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
|
|
the <a href="queryplanner-ng.html#qpstab">query planner stability guarantee</a> (QPSG). When the QPSG is active,
|
|
a single SQL query statement will always use the same algorithm regardless
|
|
of values of <a href="lang_expr.html#varparam">bound parameters</a>. The QPSG disables some query optimizations
|
|
that look at the values of bound parameters, which can make some queries
|
|
slower. But the QPSG has the advantage of more predictable behavior. With
|
|
the QPSG active, SQLite will always use the same query plan in the field as
|
|
was used during testing in the lab.
|
|
The first argument to this setting is an integer which is 0 to disable
|
|
the QPSG, positive to enable QPSG, or negative to leave the setting
|
|
unchanged. The second parameter is a pointer to an integer into which
|
|
is written 0 or 1 to indicate whether the QPSG is disabled or enabled
|
|
following this call.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfigtriggereqp"></a>
|
|
<dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
|
|
<dd> By default, the output of EXPLAIN QUERY PLAN commands does not
|
|
include output for any operations performed by trigger programs. This
|
|
option is used to set or clear (the default) a flag that governs this
|
|
behavior. The first parameter passed to this operation is an integer -
|
|
positive to enable output for trigger programs, or zero to disable it,
|
|
or negative to leave the setting unchanged.
|
|
The second parameter is a pointer to an integer into which is written
|
|
0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
|
|
it is not disabled, 1 if it is.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfigresetdatabase"></a>
|
|
<dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
|
|
<dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
|
|
<a href="lang_vacuum.html">VACUUM</a> in order to reset a database back to an empty database
|
|
with no schema and no content. The following process works even for
|
|
a badly corrupted database file:
|
|
<ol>
|
|
<li> If the database connection is newly opened, make sure it has read the
|
|
database schema by preparing then discarding some query against the
|
|
database, or calling sqlite3_table_column_metadata(), ignoring any
|
|
errors. This step is only necessary if the application desires to keep
|
|
the database in WAL mode after the reset if it was in WAL mode before
|
|
the reset.
|
|
<li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
|
|
<li> <a href="#sqlite3_exec">sqlite3_exec</a>(db, "<a href="lang_vacuum.html">VACUUM</a>", 0, 0, 0);
|
|
<li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
|
|
</ol>
|
|
Because resetting a database is destructive and irreversible, the
|
|
process requires the use of this obscure API and multiple steps to help
|
|
ensure that it does not happen by accident.</p>
|
|
|
|
<p><a name="sqlitedbconfigdefensive"></a>
|
|
<dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
|
|
<dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
|
|
"defensive" flag for a database connection. When the defensive
|
|
flag is enabled, language features that allow ordinary SQL to
|
|
deliberately corrupt the database file are disabled. The disabled
|
|
features include but are not limited to the following:
|
|
<ul>
|
|
<li> The <a href="pragma.html#pragma_writable_schema">PRAGMA writable_schema=ON</a> statement.
|
|
<li> The <a href="pragma.html#pragma_journal_mode">PRAGMA journal_mode=OFF</a> statement.
|
|
<li> Writes to the <a href="dbpage.html">sqlite_dbpage</a> virtual table.
|
|
<li> Direct writes to <a href="vtab.html#xshadowname">shadow tables</a>.
|
|
</ul>
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfigwritableschema"></a>
|
|
<dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
|
|
<dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
|
|
"writable_schema" flag. This has the same effect and is logically equivalent
|
|
to setting <a href="pragma.html#pragma_writable_schema">PRAGMA writable_schema=ON</a> or <a href="pragma.html#pragma_writable_schema">PRAGMA writable_schema=OFF</a>.
|
|
The first argument to this setting is an integer which is 0 to disable
|
|
the writable_schema, positive to enable writable_schema, or negative to
|
|
leave the setting unchanged. The second parameter is a pointer to an
|
|
integer into which is written 0 or 1 to indicate whether the writable_schema
|
|
is enabled or disabled following this call.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfiglegacyaltertable"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
|
|
<dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
|
|
the legacy behavior of the <a href="lang_altertable.html#altertabrename">ALTER TABLE RENAME</a> command such it
|
|
behaves as it did prior to <a href="releaselog/3_24_0.html">version 3.24.0</a> (2018-06-04). See the
|
|
"Compatibility Notice" on the <a href="lang_altertable.html#altertabrename">ALTER TABLE RENAME documentation</a> for
|
|
additional information. This feature can also be turned on and off
|
|
using the <a href="pragma.html#pragma_legacy_alter_table">PRAGMA legacy_alter_table</a> statement.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfigdqsdml"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_DQS_DML</td>
|
|
<dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
|
|
the legacy <a href="quirks.html#dblquote">double-quoted string literal</a> misfeature for DML statements
|
|
only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
|
|
default value of this setting is determined by the <a href="compile.html#dqs">-DSQLITE_DQS</a>
|
|
compile-time option.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfigdqsddl"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_DQS_DDL</td>
|
|
<dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
|
|
the legacy <a href="quirks.html#dblquote">double-quoted string literal</a> misfeature for DDL statements,
|
|
such as CREATE TABLE and CREATE INDEX. The
|
|
default value of this setting is determined by the <a href="compile.html#dqs">-DSQLITE_DQS</a>
|
|
compile-time option.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfigtrustedschema"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</td>
|
|
<dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
|
|
assume that database schemas are untainted by malicious content.
|
|
When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
|
|
takes additional defensive steps to protect the application from harm
|
|
including:
|
|
<ul>
|
|
<li> Prohibit the use of SQL functions inside triggers, views,
|
|
CHECK constraints, DEFAULT clauses, expression indexes,
|
|
partial indexes, or generated columns
|
|
unless those functions are tagged with <a href="#sqliteinnocuous">SQLITE_INNOCUOUS</a>.
|
|
<li> Prohibit the use of virtual tables inside of triggers or views
|
|
unless those virtual tables are tagged with <a href="#sqlitevtabinnocuous">SQLITE_VTAB_INNOCUOUS</a>.
|
|
</ul>
|
|
This setting defaults to "on" for legacy compatibility, however
|
|
all applications are advised to turn it off if possible. This setting
|
|
can also be controlled using the <a href="pragma.html#pragma_trusted_schema">PRAGMA trusted_schema</a> statement.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbconfiglegacyfileformat"></a>
|
|
|
|
<dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</td>
|
|
<dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
|
|
the legacy file format flag. When activated, this flag causes all newly
|
|
created database file to have a schema format version number (the 4-byte
|
|
integer found at offset 44 into the database header) of 1. This in turn
|
|
means that the resulting database file will be readable and writable by
|
|
any SQLite version back to 3.0.0 (2004-06-18). Without this setting,
|
|
newly created databases are generally not understandable by SQLite versions
|
|
prior to 3.3.0 (2006-01-11). As these words are written, there
|
|
is now scarcely any need to generated database files that are compatible
|
|
all the way back to version 3.0.0, and so this setting is of little
|
|
practical use, but is provided so that SQLite can continue to claim the
|
|
ability to generate new database files that are compatible with version
|
|
3.0.0.
|
|
<p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
|
|
the <a href="lang_vacuum.html">VACUUM</a> command will fail with an obscure error when attempting to
|
|
process a table with generated columns and a descending index. This is
|
|
not considered a bug since SQLite versions 3.3.0 and earlier do not support
|
|
either generated columns or decending indexes.
|
|
</dd>
|
|
</dl>
|
|
</p><hr><a name="SQLITE_DENY"></a>
|
|
<h2>Authorizer Return Codes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_DENY 1 /* Abort the SQL statement with an error */
|
|
#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_set_authorizer">authorizer callback function</a> must
|
|
return either <a href="#SQLITE_ABORT">SQLITE_OK</a> or one of these two constants in order
|
|
to signal SQLite whether or not the action is permitted. See the
|
|
<a href="#sqlite3_set_authorizer">authorizer documentation</a> for additional
|
|
information.</p>
|
|
|
|
<p>Note that SQLITE_IGNORE is also used as a <a href="#SQLITE_FAIL">conflict resolution mode</a>
|
|
returned from the <a href="#sqlite3_vtab_on_conflict">sqlite3_vtab_on_conflict()</a> interface.
|
|
</p><hr><a name="SQLITE_DESERIALIZE_FREEONCLOSE"></a>
|
|
<h2>Flags for sqlite3_deserialize()</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
|
|
#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */
|
|
#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */
|
|
</pre></blockquote>
|
|
<p>
|
|
The following are allowed values for 6th argument (the F argument) to
|
|
the <a href="#sqlite3_deserialize">sqlite3_deserialize(D,S,P,N,M,F)</a> interface.</p>
|
|
|
|
<p>The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
|
|
in the P argument is held in memory obtained from <a href="#sqlite3_free">sqlite3_malloc64()</a>
|
|
and that SQLite should take ownership of this memory and automatically
|
|
free it when it has finished using it. Without this flag, the caller
|
|
is responsible for freeing any dynamically allocated memory.</p>
|
|
|
|
<p>The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
|
|
grow the size of the database using calls to <a href="#sqlite3_free">sqlite3_realloc64()</a>. This
|
|
flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
|
|
Without this flag, the deserialized database cannot increase in size beyond
|
|
the number of bytes specified by the M parameter.</p>
|
|
|
|
<p>The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
|
|
should be treated as read-only.
|
|
</p><hr><a name="SQLITE_DETERMINISTIC"></a>
|
|
<h2>Function Flags</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_DETERMINISTIC 0x000000800
|
|
#define SQLITE_DIRECTONLY 0x000080000
|
|
#define SQLITE_SUBTYPE 0x000100000
|
|
#define SQLITE_INNOCUOUS 0x000200000
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants may be ORed together with the
|
|
<a href="#SQLITE_ANY">preferred text encoding</a> as the fourth argument
|
|
to <a href="#sqlite3_create_function">sqlite3_create_function()</a>, <a href="#sqlite3_create_function">sqlite3_create_function16()</a>, or
|
|
<a href="#sqlite3_create_function">sqlite3_create_function_v2()</a>.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitedeterministic"></a>
|
|
<dt>SQLITE_DETERMINISTIC</dt><dd>
|
|
The SQLITE_DETERMINISTIC flag means that the new function always gives
|
|
the same output when the input parameters are the same.
|
|
The <a href="lang_corefunc.html#abs">abs() function</a> is deterministic, for example, but
|
|
<a href="lang_corefunc.html#randomblob">randomblob()</a> is not. Functions must
|
|
be deterministic in order to be used in certain contexts such as
|
|
with the WHERE clause of <a href="partialindex.html">partial indexes</a> or in <a href="gencol.html">generated columns</a>.
|
|
SQLite might also optimize deterministic functions by factoring them
|
|
out of inner loops.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedirectonly"></a>
|
|
<dt>SQLITE_DIRECTONLY</dt><dd>
|
|
The SQLITE_DIRECTONLY flag means that the function may only be invoked
|
|
from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
|
|
schema structures such as <a href="lang_createtable.html#ckconst">CHECK constraints</a>, <a href="lang_createtable.html#dfltval">DEFAULT clauses</a>,
|
|
<a href="expridx.html">expression indexes</a>, <a href="partialindex.html">partial indexes</a>, or <a href="gencol.html">generated columns</a>.
|
|
The SQLITE_DIRECTONLY flags is a security feature which is recommended
|
|
for all <a href="appfunc.html">application-defined SQL functions</a>, and especially for functions
|
|
that have side-effects or that could potentially leak sensitive
|
|
information.
|
|
</dd></p>
|
|
|
|
<p><a name="sqliteinnocuous"></a>
|
|
<dt>SQLITE_INNOCUOUS</dt><dd>
|
|
The SQLITE_INNOCUOUS flag means that the function is unlikely
|
|
to cause problems even if misused. An innocuous function should have
|
|
no side effects and should not depend on any values other than its
|
|
input parameters. The <a href="lang_corefunc.html#abs">abs() function</a> is an example of an
|
|
innocuous function.
|
|
The <a href="lang_corefunc.html#load_extension">load_extension() SQL function</a> is not innocuous because of its
|
|
side effects.
|
|
<p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
|
|
exactly the same. The <a href="lang_corefunc.html#random">random() function</a> is an example of a
|
|
function that is innocuous but not deterministic.
|
|
<p>Some heightened security settings
|
|
(<a href="#sqlitedbconfigtrustedschema">SQLITE_DBCONFIG_TRUSTED_SCHEMA</a> and <a href="pragma.html#pragma_trusted_schema">PRAGMA trusted_schema=OFF</a>)
|
|
disable the use of SQL functions inside views and triggers and in
|
|
schema structures such as <a href="lang_createtable.html#ckconst">CHECK constraints</a>, <a href="lang_createtable.html#dfltval">DEFAULT clauses</a>,
|
|
<a href="expridx.html">expression indexes</a>, <a href="partialindex.html">partial indexes</a>, and <a href="gencol.html">generated columns</a> unless
|
|
the function is tagged with SQLITE_INNOCUOUS. Most built-in functions
|
|
are innocuous. Developers are advised to avoid using the
|
|
SQLITE_INNOCUOUS flag for application-defined functions unless the
|
|
function has been carefully audited and found to be free of potentially
|
|
security-adverse side-effects and information-leaks.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitesubtype"></a>
|
|
<dt>SQLITE_SUBTYPE</dt><dd>
|
|
The SQLITE_SUBTYPE flag indicates to SQLite that a function may call
|
|
<a href="#sqlite3_value_subtype">sqlite3_value_subtype()</a> to inspect the sub-types of its arguments.
|
|
Specifying this flag makes no difference for scalar or aggregate user
|
|
functions. However, if it is not specified for a user-defined window
|
|
function, then any sub-types belonging to arguments passed to the window
|
|
function may be discarded before the window function is called (i.e.
|
|
sqlite3_value_subtype() will always return 0).
|
|
</dd>
|
|
</dl>
|
|
</p><hr><a name="SQLITE_FAIL"></a>
|
|
<h2>Conflict resolution modes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_ROLLBACK 1
|
|
/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
|
|
#define SQLITE_FAIL 3
|
|
/* #define SQLITE_ABORT 4 // Also an error code */
|
|
#define SQLITE_REPLACE 5
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants are returned by <a href="#sqlite3_vtab_on_conflict">sqlite3_vtab_on_conflict()</a> to
|
|
inform a <a href="vtab.html">virtual table</a> implementation what the <a href="lang_conflict.html">ON CONFLICT</a> mode
|
|
is for the SQL statement being evaluated.</p>
|
|
|
|
<p>Note that the <a href="#SQLITE_DENY">SQLITE_IGNORE</a> constant is also used as a potential
|
|
return value from the <a href="#sqlite3_set_authorizer">sqlite3_set_authorizer()</a> callback and that
|
|
<a href="#SQLITE_ABORT">SQLITE_ABORT</a> is also a <a href="rescode.html">result code</a>.
|
|
</p><hr><a name="SQLITE_FCNTL_BEGIN_ATOMIC_WRITE"></a>
|
|
<h2>Standard File Control Opcodes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_FCNTL_LOCKSTATE 1
|
|
#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2
|
|
#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3
|
|
#define SQLITE_FCNTL_LAST_ERRNO 4
|
|
#define SQLITE_FCNTL_SIZE_HINT 5
|
|
#define SQLITE_FCNTL_CHUNK_SIZE 6
|
|
#define SQLITE_FCNTL_FILE_POINTER 7
|
|
#define SQLITE_FCNTL_SYNC_OMITTED 8
|
|
#define SQLITE_FCNTL_WIN32_AV_RETRY 9
|
|
#define SQLITE_FCNTL_PERSIST_WAL 10
|
|
#define SQLITE_FCNTL_OVERWRITE 11
|
|
#define SQLITE_FCNTL_VFSNAME 12
|
|
#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13
|
|
#define SQLITE_FCNTL_PRAGMA 14
|
|
#define SQLITE_FCNTL_BUSYHANDLER 15
|
|
#define SQLITE_FCNTL_TEMPFILENAME 16
|
|
#define SQLITE_FCNTL_MMAP_SIZE 18
|
|
#define SQLITE_FCNTL_TRACE 19
|
|
#define SQLITE_FCNTL_HAS_MOVED 20
|
|
#define SQLITE_FCNTL_SYNC 21
|
|
#define SQLITE_FCNTL_COMMIT_PHASETWO 22
|
|
#define SQLITE_FCNTL_WIN32_SET_HANDLE 23
|
|
#define SQLITE_FCNTL_WAL_BLOCK 24
|
|
#define SQLITE_FCNTL_ZIPVFS 25
|
|
#define SQLITE_FCNTL_RBU 26
|
|
#define SQLITE_FCNTL_VFS_POINTER 27
|
|
#define SQLITE_FCNTL_JOURNAL_POINTER 28
|
|
#define SQLITE_FCNTL_WIN32_GET_HANDLE 29
|
|
#define SQLITE_FCNTL_PDB 30
|
|
#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31
|
|
#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32
|
|
#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33
|
|
#define SQLITE_FCNTL_LOCK_TIMEOUT 34
|
|
#define SQLITE_FCNTL_DATA_VERSION 35
|
|
#define SQLITE_FCNTL_SIZE_LIMIT 36
|
|
#define SQLITE_FCNTL_CKPT_DONE 37
|
|
#define SQLITE_FCNTL_RESERVE_BYTES 38
|
|
#define SQLITE_FCNTL_CKPT_START 39
|
|
</pre></blockquote>
|
|
<p>
|
|
These integer constants are opcodes for the xFileControl method
|
|
of the <a href="#sqlite3_io_methods">sqlite3_io_methods</a> object and for the <a href="#sqlite3_file_control">sqlite3_file_control()</a>
|
|
interface.</p>
|
|
|
|
<p><ul>
|
|
<li><a name="sqlitefcntllockstate"></a>
|
|
|
|
The <a href="#sqlitefcntllockstate">SQLITE_FCNTL_LOCKSTATE</a> opcode is used for debugging. This
|
|
opcode causes the xFileControl method to write the current state of
|
|
the lock (one of <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_NONE</a>, <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_SHARED</a>,
|
|
<a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_RESERVED</a>, <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_PENDING</a>, or <a href="#SQLITE_LOCK_EXCLUSIVE">SQLITE_LOCK_EXCLUSIVE</a>)
|
|
into an integer that the pArg argument points to. This capability
|
|
is used during testing and is only available when the SQLITE_TEST
|
|
compile-time option is used.</p>
|
|
|
|
<p><li><a name="sqlitefcntlsizehint"></a>
|
|
|
|
The <a href="#sqlitefcntlsizehint">SQLITE_FCNTL_SIZE_HINT</a> opcode is used by SQLite to give the VFS
|
|
layer a hint of how large the database file will grow to be during the
|
|
current transaction. This hint is not guaranteed to be accurate but it
|
|
is often close. The underlying VFS might choose to preallocate database
|
|
file space based on this hint in order to help writes to the database
|
|
file run faster.</p>
|
|
|
|
<p><li><a name="sqlitefcntlsizelimit"></a>
|
|
|
|
The <a href="#sqlitefcntlsizelimit">SQLITE_FCNTL_SIZE_LIMIT</a> opcode is used by in-memory VFS that
|
|
implements <a href="#sqlite3_deserialize">sqlite3_deserialize()</a> to set an upper bound on the size
|
|
of the in-memory database. The argument is a pointer to a <a href="#sqlite3_int64">sqlite3_int64</a>.
|
|
If the integer pointed to is negative, then it is filled in with the
|
|
current limit. Otherwise the limit is set to the larger of the value
|
|
of the integer pointed to and the current database size. The integer
|
|
pointed to is set to the new limit.</p>
|
|
|
|
<p><li><a name="sqlitefcntlchunksize"></a>
|
|
|
|
The <a href="#sqlitefcntlchunksize">SQLITE_FCNTL_CHUNK_SIZE</a> opcode is used to request that the VFS
|
|
extends and truncates the database file in chunks of a size specified
|
|
by the user. The fourth argument to <a href="#sqlite3_file_control">sqlite3_file_control()</a> should
|
|
point to an integer (type int) containing the new chunk-size to use
|
|
for the nominated database. Allocating database file space in large
|
|
chunks (say 1MB at a time), may reduce file-system fragmentation and
|
|
improve performance on some systems.</p>
|
|
|
|
<p><li><a name="sqlitefcntlfilepointer"></a>
|
|
|
|
The <a href="#sqlitefcntlfilepointer">SQLITE_FCNTL_FILE_POINTER</a> opcode is used to obtain a pointer
|
|
to the <a href="#sqlite3_file">sqlite3_file</a> object associated with a particular database
|
|
connection. See also <a href="#sqlitefcntljournalpointer">SQLITE_FCNTL_JOURNAL_POINTER</a>.</p>
|
|
|
|
<p><li><a name="sqlitefcntljournalpointer"></a>
|
|
|
|
The <a href="#sqlitefcntljournalpointer">SQLITE_FCNTL_JOURNAL_POINTER</a> opcode is used to obtain a pointer
|
|
to the <a href="#sqlite3_file">sqlite3_file</a> object associated with the journal file (either
|
|
the <a href="lockingv3.html#rollback">rollback journal</a> or the <a href="wal.html">write-ahead log</a>) for a particular database
|
|
connection. See also <a href="#sqlitefcntlfilepointer">SQLITE_FCNTL_FILE_POINTER</a>.</p>
|
|
|
|
<p><li><a name="sqlitefcntlsyncomitted"></a>
|
|
|
|
No longer in use.</p>
|
|
|
|
<p><li><a name="sqlitefcntlsync"></a>
|
|
|
|
The <a href="#sqlitefcntlsync">SQLITE_FCNTL_SYNC</a> opcode is generated internally by SQLite and
|
|
sent to the VFS immediately before the xSync method is invoked on a
|
|
database file descriptor. Or, if the xSync method is not invoked
|
|
because the user has configured SQLite with
|
|
<a href="pragma.html#pragma_synchronous">PRAGMA synchronous=OFF</a> it is invoked in place
|
|
of the xSync method. In most cases, the pointer argument passed with
|
|
this file-control is NULL. However, if the database file is being synced
|
|
as part of a multi-database commit, the argument points to a nul-terminated
|
|
string containing the transactions super-journal file name. VFSes that
|
|
do not need this signal should silently ignore this opcode. Applications
|
|
should not call <a href="#sqlite3_file_control">sqlite3_file_control()</a> with this opcode as doing so may
|
|
disrupt the operation of the specialized VFSes that do require it.</p>
|
|
|
|
<p><li><a name="sqlitefcntlcommitphasetwo"></a>
|
|
|
|
The <a href="#sqlitefcntlcommitphasetwo">SQLITE_FCNTL_COMMIT_PHASETWO</a> opcode is generated internally by SQLite
|
|
and sent to the VFS after a transaction has been committed immediately
|
|
but before the database is unlocked. VFSes that do not need this signal
|
|
should silently ignore this opcode. Applications should not call
|
|
<a href="#sqlite3_file_control">sqlite3_file_control()</a> with this opcode as doing so may disrupt the
|
|
operation of the specialized VFSes that do require it.</p>
|
|
|
|
<p><li><a name="sqlitefcntlwin32avretry"></a>
|
|
|
|
The <a href="#sqlitefcntlwin32avretry">SQLITE_FCNTL_WIN32_AV_RETRY</a> opcode is used to configure automatic
|
|
retry counts and intervals for certain disk I/O operations for the
|
|
windows <a href="vfs.html">VFS</a> in order to provide robustness in the presence of
|
|
anti-virus programs. By default, the windows VFS will retry file read,
|
|
file write, and file delete operations up to 10 times, with a delay
|
|
of 25 milliseconds before the first retry and with the delay increasing
|
|
by an additional 25 milliseconds with each subsequent retry. This
|
|
opcode allows these two values (10 retries and 25 milliseconds of delay)
|
|
to be adjusted. The values are changed for all database connections
|
|
within the same process. The argument is a pointer to an array of two
|
|
integers where the first integer is the new retry count and the second
|
|
integer is the delay. If either integer is negative, then the setting
|
|
is not changed but instead the prior value of that setting is written
|
|
into the array entry, allowing the current retry settings to be
|
|
interrogated. The zDbName parameter is ignored.</p>
|
|
|
|
<p><li><a name="sqlitefcntlpersistwal"></a>
|
|
|
|
The <a href="#sqlitefcntlpersistwal">SQLITE_FCNTL_PERSIST_WAL</a> opcode is used to set or query the
|
|
persistent <a href="wal.html">Write Ahead Log</a> setting. By default, the auxiliary
|
|
write ahead log (<a href="wal.html#walfile">WAL file</a>) and shared memory
|
|
files used for transaction control
|
|
are automatically deleted when the latest connection to the database
|
|
closes. Setting persistent WAL mode causes those files to persist after
|
|
close. Persisting the files is useful when other processes that do not
|
|
have write permission on the directory containing the database file want
|
|
to read the database file, as the WAL and shared memory files must exist
|
|
in order for the database to be readable. The fourth parameter to
|
|
<a href="#sqlite3_file_control">sqlite3_file_control()</a> for this opcode should be a pointer to an integer.
|
|
That integer is 0 to disable persistent WAL mode or 1 to enable persistent
|
|
WAL mode. If the integer is -1, then it is overwritten with the current
|
|
WAL persistence setting.</p>
|
|
|
|
<p><li><a name="sqlitefcntlpowersafeoverwrite"></a>
|
|
|
|
The <a href="#sqlitefcntlpowersafeoverwrite">SQLITE_FCNTL_POWERSAFE_OVERWRITE</a> opcode is used to set or query the
|
|
persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting
|
|
determines the <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_POWERSAFE_OVERWRITE</a> bit of the
|
|
xDeviceCharacteristics methods. The fourth parameter to
|
|
<a href="#sqlite3_file_control">sqlite3_file_control()</a> for this opcode should be a pointer to an integer.
|
|
That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
|
|
mode. If the integer is -1, then it is overwritten with the current
|
|
zero-damage mode setting.</p>
|
|
|
|
<p><li><a name="sqlitefcntloverwrite"></a>
|
|
|
|
The <a href="#sqlitefcntloverwrite">SQLITE_FCNTL_OVERWRITE</a> opcode is invoked by SQLite after opening
|
|
a write transaction to indicate that, unless it is rolled back for some
|
|
reason, the entire database file will be overwritten by the current
|
|
transaction. This is used by VACUUM operations.</p>
|
|
|
|
<p><li><a name="sqlitefcntlvfsname"></a>
|
|
|
|
The <a href="#sqlitefcntlvfsname">SQLITE_FCNTL_VFSNAME</a> opcode can be used to obtain the names of
|
|
all <a href="vfs.html">VFSes</a> in the VFS stack. The names are of all VFS shims and the
|
|
final bottom-level VFS are written into memory obtained from
|
|
<a href="#sqlite3_free">sqlite3_malloc()</a> and the result is stored in the char* variable
|
|
that the fourth parameter of <a href="#sqlite3_file_control">sqlite3_file_control()</a> points to.
|
|
The caller is responsible for freeing the memory when done. As with
|
|
all file-control actions, there is no guarantee that this will actually
|
|
do anything. Callers should initialize the char* variable to a NULL
|
|
pointer in case this file-control is not implemented. This file-control
|
|
is intended for diagnostic use only.</p>
|
|
|
|
<p><li><a name="sqlitefcntlvfspointer"></a>
|
|
|
|
The <a href="#sqlitefcntlvfspointer">SQLITE_FCNTL_VFS_POINTER</a> opcode finds a pointer to the top-level
|
|
<a href="vfs.html">VFSes</a> currently in use. The argument X in
|
|
sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
|
|
of type "<a href="#sqlite3_vfs">sqlite3_vfs</a> **". This opcodes will set *X
|
|
to a pointer to the top-level VFS.
|
|
When there are multiple VFS shims in the stack, this opcode finds the
|
|
upper-most shim only.</p>
|
|
|
|
<p><li><a name="sqlitefcntlpragma"></a>
|
|
|
|
Whenever a <a href="pragma.html#syntax">PRAGMA</a> statement is parsed, an <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a>
|
|
file control is sent to the open <a href="#sqlite3_file">sqlite3_file</a> object corresponding
|
|
to the database file to which the pragma statement refers. The argument
|
|
to the <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a> file control is an array of
|
|
pointers to strings (char**) in which the second element of the array
|
|
is the name of the pragma and the third element is the argument to the
|
|
pragma or NULL if the pragma has no argument. The handler for an
|
|
<a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a> file control can optionally make the first element
|
|
of the char** argument point to a string obtained from <a href="#sqlite3_mprintf">sqlite3_mprintf()</a>
|
|
or the equivalent and that string will become the result of the pragma or
|
|
the error message if the pragma fails. If the
|
|
<a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a> file control returns <a href="#SQLITE_ABORT">SQLITE_NOTFOUND</a>, then normal
|
|
<a href="pragma.html#syntax">PRAGMA</a> processing continues. If the <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a>
|
|
file control returns <a href="#SQLITE_ABORT">SQLITE_OK</a>, then the parser assumes that the
|
|
VFS has handled the PRAGMA itself and the parser generates a no-op
|
|
prepared statement if result string is NULL, or that returns a copy
|
|
of the result string if the string is non-NULL.
|
|
If the <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a> file control returns
|
|
any result code other than <a href="#SQLITE_ABORT">SQLITE_OK</a> or <a href="#SQLITE_ABORT">SQLITE_NOTFOUND</a>, that means
|
|
that the VFS encountered an error while handling the <a href="pragma.html#syntax">PRAGMA</a> and the
|
|
compilation of the PRAGMA fails with an error. The <a href="#sqlitefcntlpragma">SQLITE_FCNTL_PRAGMA</a>
|
|
file control occurs at the beginning of pragma statement analysis and so
|
|
it is able to override built-in <a href="pragma.html#syntax">PRAGMA</a> statements.</p>
|
|
|
|
<p><li><a name="sqlitefcntlbusyhandler"></a>
|
|
|
|
The <a href="#sqlitefcntlbusyhandler">SQLITE_FCNTL_BUSYHANDLER</a>
|
|
file-control may be invoked by SQLite on the database file handle
|
|
shortly after it is opened in order to provide a custom VFS with access
|
|
to the connection's busy-handler callback. The argument is of type (void**)
|
|
- an array of two (void *) values. The first (void *) actually points
|
|
to a function of type (int (*)(void *)). In order to invoke the connection's
|
|
busy-handler, this function should be invoked with the second (void *) in
|
|
the array as the only argument. If it returns non-zero, then the operation
|
|
should be retried. If it returns zero, the custom VFS should abandon the
|
|
current operation.</p>
|
|
|
|
<p><li><a name="sqlitefcntltempfilename"></a>
|
|
|
|
Applications can invoke the <a href="#sqlitefcntltempfilename">SQLITE_FCNTL_TEMPFILENAME</a> file-control
|
|
to have SQLite generate a
|
|
temporary filename using the same algorithm that is followed to generate
|
|
temporary filenames for TEMP tables and other internal uses. The
|
|
argument should be a char** which will be filled with the filename
|
|
written into memory obtained from <a href="#sqlite3_free">sqlite3_malloc()</a>. The caller should
|
|
invoke <a href="#sqlite3_free">sqlite3_free()</a> on the result to avoid a memory leak.</p>
|
|
|
|
<p><li><a name="sqlitefcntlmmapsize"></a>
|
|
|
|
The <a href="#sqlitefcntlmmapsize">SQLITE_FCNTL_MMAP_SIZE</a> file control is used to query or set the
|
|
maximum number of bytes that will be used for memory-mapped I/O.
|
|
The argument is a pointer to a value of type sqlite3_int64 that
|
|
is an advisory maximum number of bytes in the file to memory map. The
|
|
pointer is overwritten with the old value. The limit is not changed if
|
|
the value originally pointed to is negative, and so the current limit
|
|
can be queried by passing in a pointer to a negative number. This
|
|
file-control is used internally to implement <a href="pragma.html#pragma_mmap_size">PRAGMA mmap_size</a>.</p>
|
|
|
|
<p><li><a name="sqlitefcntltrace"></a>
|
|
|
|
The <a href="#sqlitefcntltrace">SQLITE_FCNTL_TRACE</a> file control provides advisory information
|
|
to the VFS about what the higher layers of the SQLite stack are doing.
|
|
This file control is used by some VFS activity tracing <a href="vfs.html#shim">shims</a>.
|
|
The argument is a zero-terminated string. Higher layers in the
|
|
SQLite stack may generate instances of this file control if
|
|
the <a href="compile.html#use_fcntl_trace">SQLITE_USE_FCNTL_TRACE</a> compile-time option is enabled.</p>
|
|
|
|
<p><li><a name="sqlitefcntlhasmoved"></a>
|
|
|
|
The <a href="#sqlitefcntlhasmoved">SQLITE_FCNTL_HAS_MOVED</a> file control interprets its argument as a
|
|
pointer to an integer and it writes a boolean into that integer depending
|
|
on whether or not the file has been renamed, moved, or deleted since it
|
|
was first opened.</p>
|
|
|
|
<p><li><a name="sqlitefcntlwin32gethandle"></a>
|
|
|
|
The <a href="#sqlitefcntlwin32gethandle">SQLITE_FCNTL_WIN32_GET_HANDLE</a> opcode can be used to obtain the
|
|
underlying native file handle associated with a file handle. This file
|
|
control interprets its argument as a pointer to a native file handle and
|
|
writes the resulting value there.</p>
|
|
|
|
<p><li><a name="sqlitefcntlwin32sethandle"></a>
|
|
|
|
The <a href="#sqlitefcntlwin32sethandle">SQLITE_FCNTL_WIN32_SET_HANDLE</a> opcode is used for debugging. This
|
|
opcode causes the xFileControl method to swap the file handle with the one
|
|
pointed to by the pArg argument. This capability is used during testing
|
|
and only needs to be supported when SQLITE_TEST is defined.</p>
|
|
|
|
<p><li><a name="sqlitefcntlwalblock"></a>
|
|
|
|
The <a href="#sqlitefcntlwalblock">SQLITE_FCNTL_WAL_BLOCK</a> is a signal to the VFS layer that it might
|
|
be advantageous to block on the next WAL lock if the lock is not immediately
|
|
available. The WAL subsystem issues this signal during rare
|
|
circumstances in order to fix a problem with priority inversion.
|
|
Applications should <em>not</em> use this file-control.</p>
|
|
|
|
<p><li><a name="sqlitefcntlzipvfs"></a>
|
|
|
|
The <a href="#sqlitefcntlzipvfs">SQLITE_FCNTL_ZIPVFS</a> opcode is implemented by zipvfs only. All other
|
|
VFS should return SQLITE_NOTFOUND for this opcode.</p>
|
|
|
|
<p><li><a name="sqlitefcntlrbu"></a>
|
|
|
|
The <a href="#sqlitefcntlrbu">SQLITE_FCNTL_RBU</a> opcode is implemented by the special VFS used by
|
|
the RBU extension only. All other VFS should return SQLITE_NOTFOUND for
|
|
this opcode.</p>
|
|
|
|
<p><li><a name="sqlitefcntlbeginatomicwrite"></a>
|
|
|
|
If the <a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a> opcode returns SQLITE_OK, then
|
|
the file descriptor is placed in "batch write mode", which
|
|
means all subsequent write operations will be deferred and done
|
|
atomically at the next <a href="#sqlitefcntlcommitatomicwrite">SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a>. Systems
|
|
that do not support batch atomic writes will return SQLITE_NOTFOUND.
|
|
Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
|
|
the closing <a href="#sqlitefcntlcommitatomicwrite">SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a> or
|
|
<a href="#sqlitefcntlrollbackatomicwrite">SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE</a>, SQLite will make
|
|
no VFS interface calls on the same <a href="#sqlite3_file">sqlite3_file</a> file descriptor
|
|
except for calls to the xWrite method and the xFileControl method
|
|
with <a href="#sqlitefcntlsizehint">SQLITE_FCNTL_SIZE_HINT</a>.</p>
|
|
|
|
<p><li><a name="sqlitefcntlcommitatomicwrite"></a>
|
|
|
|
The <a href="#sqlitefcntlcommitatomicwrite">SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a> opcode causes all write
|
|
operations since the previous successful call to
|
|
<a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a> to be performed atomically.
|
|
This file control returns <a href="#SQLITE_ABORT">SQLITE_OK</a> if and only if the writes were
|
|
all performed successfully and have been committed to persistent storage.
|
|
Regardless of whether or not it is successful, this file control takes
|
|
the file descriptor out of batch write mode so that all subsequent
|
|
write operations are independent.
|
|
SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
|
|
a prior successful call to <a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a>.</p>
|
|
|
|
<p><li><a name="sqlitefcntlrollbackatomicwrite"></a>
|
|
|
|
The <a href="#sqlitefcntlrollbackatomicwrite">SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE</a> opcode causes all write
|
|
operations since the previous successful call to
|
|
<a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a> to be rolled back.
|
|
This file control takes the file descriptor out of batch write mode
|
|
so that all subsequent write operations are independent.
|
|
SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
|
|
a prior successful call to <a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a>.</p>
|
|
|
|
<p><li><a name="sqlitefcntllocktimeout"></a>
|
|
|
|
The <a href="#sqlitefcntllocktimeout">SQLITE_FCNTL_LOCK_TIMEOUT</a> opcode is used to configure a VFS
|
|
to block for up to M milliseconds before failing when attempting to
|
|
obtain a file lock using the xLock or xShmLock methods of the VFS.
|
|
The parameter is a pointer to a 32-bit signed integer that contains
|
|
the value that M is to be set to. Before returning, the 32-bit signed
|
|
integer is overwritten with the previous value of M.</p>
|
|
|
|
<p><li><a name="sqlitefcntldataversion"></a>
|
|
|
|
The <a href="#sqlitefcntldataversion">SQLITE_FCNTL_DATA_VERSION</a> opcode is used to detect changes to
|
|
a database file. The argument is a pointer to a 32-bit unsigned integer.
|
|
The "data version" for the pager is written into the pointer. The
|
|
"data version" changes whenever any change occurs to the corresponding
|
|
database file, either through SQL statements on the same database
|
|
connection or through transactions committed by separate database
|
|
connections possibly in other processes. The <a href="#sqlite3_total_changes">sqlite3_total_changes()</a>
|
|
interface can be used to find if any database on the connection has changed,
|
|
but that interface responds to changes on TEMP as well as MAIN and does
|
|
not provide a mechanism to detect changes to MAIN only. Also, the
|
|
<a href="#sqlite3_total_changes">sqlite3_total_changes()</a> interface responds to internal changes only and
|
|
omits changes made by other database connections. The
|
|
<a href="pragma.html#pragma_data_version">PRAGMA data_version</a> command provides a mechanism to detect changes to
|
|
a single attached database that occur due to other database connections,
|
|
but omits changes implemented by the database connection on which it is
|
|
called. This file control is the only mechanism to detect changes that
|
|
happen either internally or externally and that are associated with
|
|
a particular attached database.</p>
|
|
|
|
<p><li><a name="sqlitefcntlckptstart"></a>
|
|
|
|
The <a href="#sqlitefcntlckptstart">SQLITE_FCNTL_CKPT_START</a> opcode is invoked from within a checkpoint
|
|
in wal mode before the client starts to copy pages from the wal
|
|
file to the database file.</p>
|
|
|
|
<p><li><a name="sqlitefcntlckptdone"></a>
|
|
|
|
The <a href="#sqlitefcntlckptdone">SQLITE_FCNTL_CKPT_DONE</a> opcode is invoked from within a checkpoint
|
|
in wal mode after the client has finished copying pages from the wal
|
|
file to the database file, but before the *-shm file is updated to
|
|
record the fact that the pages have been checkpointed.
|
|
</ul>
|
|
</p><hr><a name="SQLITE_INDEX_CONSTRAINT_EQ"></a>
|
|
<h2>Virtual Table Constraint Operator Codes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_INDEX_CONSTRAINT_EQ 2
|
|
#define SQLITE_INDEX_CONSTRAINT_GT 4
|
|
#define SQLITE_INDEX_CONSTRAINT_LE 8
|
|
#define SQLITE_INDEX_CONSTRAINT_LT 16
|
|
#define SQLITE_INDEX_CONSTRAINT_GE 32
|
|
#define SQLITE_INDEX_CONSTRAINT_MATCH 64
|
|
#define SQLITE_INDEX_CONSTRAINT_LIKE 65
|
|
#define SQLITE_INDEX_CONSTRAINT_GLOB 66
|
|
#define SQLITE_INDEX_CONSTRAINT_REGEXP 67
|
|
#define SQLITE_INDEX_CONSTRAINT_NE 68
|
|
#define SQLITE_INDEX_CONSTRAINT_ISNOT 69
|
|
#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
|
|
#define SQLITE_INDEX_CONSTRAINT_ISNULL 71
|
|
#define SQLITE_INDEX_CONSTRAINT_IS 72
|
|
#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150
|
|
</pre></blockquote>
|
|
<p>
|
|
These macros define the allowed values for the
|
|
<a href="#sqlite3_index_info">sqlite3_index_info</a>.aConstraint[].op field. Each value represents
|
|
an operator that is part of a constraint term in the wHERE clause of
|
|
a query that uses a <a href="vtab.html">virtual table</a>.
|
|
</p><hr><a name="SQLITE_IOCAP_ATOMIC"></a>
|
|
<h2>Device Characteristics</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_IOCAP_ATOMIC 0x00000001
|
|
#define SQLITE_IOCAP_ATOMIC512 0x00000002
|
|
#define SQLITE_IOCAP_ATOMIC1K 0x00000004
|
|
#define SQLITE_IOCAP_ATOMIC2K 0x00000008
|
|
#define SQLITE_IOCAP_ATOMIC4K 0x00000010
|
|
#define SQLITE_IOCAP_ATOMIC8K 0x00000020
|
|
#define SQLITE_IOCAP_ATOMIC16K 0x00000040
|
|
#define SQLITE_IOCAP_ATOMIC32K 0x00000080
|
|
#define SQLITE_IOCAP_ATOMIC64K 0x00000100
|
|
#define SQLITE_IOCAP_SAFE_APPEND 0x00000200
|
|
#define SQLITE_IOCAP_SEQUENTIAL 0x00000400
|
|
#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800
|
|
#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000
|
|
#define SQLITE_IOCAP_IMMUTABLE 0x00002000
|
|
#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000
|
|
</pre></blockquote>
|
|
<p>
|
|
The xDeviceCharacteristics method of the <a href="#sqlite3_io_methods">sqlite3_io_methods</a>
|
|
object returns an integer which is a vector of these
|
|
bit values expressing I/O characteristics of the mass storage
|
|
device that holds the file that the <a href="#sqlite3_io_methods">sqlite3_io_methods</a>
|
|
refers to.</p>
|
|
|
|
<p>The SQLITE_IOCAP_ATOMIC property means that all writes of
|
|
any size are atomic. The SQLITE_IOCAP_ATOMICnnn values
|
|
mean that writes of blocks that are nnn bytes in size and
|
|
are aligned to an address which is an integer multiple of
|
|
nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means
|
|
that when data is appended to a file, the data is appended
|
|
first then the size of the file is extended, never the other
|
|
way around. The SQLITE_IOCAP_SEQUENTIAL property means that
|
|
information is written to disk in the same order as calls
|
|
to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
|
|
after reboot following a crash or power loss, the only bytes in a
|
|
file that were written at the application level might have changed
|
|
and that adjacent bytes, even bytes within the same sector are
|
|
guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
|
|
flag indicates that a file cannot be deleted when open. The
|
|
SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
|
|
read-only media and cannot be changed even by processes with
|
|
elevated privileges.</p>
|
|
|
|
<p>The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
|
|
filesystem supports doing multiple write operations atomically when those
|
|
write operations are bracketed by <a href="#sqlitefcntlbeginatomicwrite">SQLITE_FCNTL_BEGIN_ATOMIC_WRITE</a> and
|
|
<a href="#sqlitefcntlcommitatomicwrite">SQLITE_FCNTL_COMMIT_ATOMIC_WRITE</a>.
|
|
</p><hr><a name="SQLITE_LOCK_EXCLUSIVE"></a>
|
|
<h2>File Locking Levels</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_LOCK_NONE 0
|
|
#define SQLITE_LOCK_SHARED 1
|
|
#define SQLITE_LOCK_RESERVED 2
|
|
#define SQLITE_LOCK_PENDING 3
|
|
#define SQLITE_LOCK_EXCLUSIVE 4
|
|
</pre></blockquote>
|
|
<p>
|
|
SQLite uses one of these integer values as the second
|
|
argument to calls it makes to the xLock() and xUnlock() methods
|
|
of an <a href="#sqlite3_io_methods">sqlite3_io_methods</a> object.
|
|
</p><hr><a name="SQLITE_MUTEX_FAST"></a>
|
|
<h2>Mutex Types</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_MUTEX_FAST 0
|
|
#define SQLITE_MUTEX_RECURSIVE 1
|
|
#define SQLITE_MUTEX_STATIC_MAIN 2
|
|
#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */
|
|
#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */
|
|
#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */
|
|
#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */
|
|
#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */
|
|
#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */
|
|
#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */
|
|
#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */
|
|
#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */
|
|
#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */
|
|
#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */
|
|
#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */
|
|
#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_mutex_alloc">sqlite3_mutex_alloc()</a> interface takes a single argument
|
|
which is one of these integer constants.</p>
|
|
|
|
<p>The set of static mutexes may change from one SQLite release to the
|
|
next. Applications that override the built-in mutex logic must be
|
|
prepared to accommodate additional static mutexes.
|
|
</p><hr><a name="SQLITE_OPEN_AUTOPROXY"></a>
|
|
<h2>Flags For File Open Operations</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */
|
|
#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */
|
|
#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */
|
|
#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */
|
|
#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */
|
|
#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */
|
|
#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */
|
|
#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */
|
|
#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */
|
|
#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */
|
|
#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */
|
|
#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */
|
|
#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */
|
|
#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */
|
|
#define SQLITE_OPEN_SUPER_JOURNAL 0x00004000 /* VFS only */
|
|
#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */
|
|
#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */
|
|
#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */
|
|
#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */
|
|
#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */
|
|
#define SQLITE_OPEN_NOFOLLOW 0x01000000 /* Ok for sqlite3_open_v2() */
|
|
</pre></blockquote>
|
|
<p>
|
|
These bit values are intended for use in the
|
|
3rd parameter to the <a href="#sqlite3_open">sqlite3_open_v2()</a> interface and
|
|
in the 4th parameter to the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen</a> method.
|
|
</p><hr><a name="SQLITE_PREPARE_NORMALIZE"></a>
|
|
<h2>Prepare Flags</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_PREPARE_PERSISTENT 0x01
|
|
#define SQLITE_PREPARE_NORMALIZE 0x02
|
|
#define SQLITE_PREPARE_NO_VTAB 0x04
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants define various flags that can be passed into
|
|
"prepFlags" parameter of the <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a> and
|
|
<a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a> interfaces.</p>
|
|
|
|
<p>New flags may be added in future releases of SQLite.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitepreparepersistent"></a>
|
|
<dt>SQLITE_PREPARE_PERSISTENT</dt>
|
|
<dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
|
|
that the prepared statement will be retained for a long time and
|
|
probably reused many times. Without this flag, <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>
|
|
and <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a> assume that the prepared statement will
|
|
be used just once or at most a few times and then destroyed using
|
|
<a href="#sqlite3_finalize">sqlite3_finalize()</a> relatively soon. The current implementation acts
|
|
on this hint by avoiding the use of <a href="malloc.html#lookaside">lookaside memory</a> so as not to
|
|
deplete the limited store of lookaside memory. Future versions of
|
|
SQLite may act on this hint differently.</p>
|
|
|
|
<p><a name="sqlitepreparenormalize"></a>
|
|
<dt>SQLITE_PREPARE_NORMALIZE</dt>
|
|
<dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
|
|
to be required for any prepared statement that wanted to use the
|
|
<a href="#sqlite3_expanded_sql">sqlite3_normalized_sql()</a> interface. However, the
|
|
<a href="#sqlite3_expanded_sql">sqlite3_normalized_sql()</a> interface is now available to all
|
|
prepared statements, regardless of whether or not they use this
|
|
flag.</p>
|
|
|
|
<p><a name="sqlitepreparenovtab"></a>
|
|
<dt>SQLITE_PREPARE_NO_VTAB</dt>
|
|
<dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
|
|
to return an error (error code SQLITE_ERROR) if the statement uses
|
|
any virtual tables.
|
|
</dl>
|
|
</p><hr><a name="SQLITE_SCANSTAT_EST"></a>
|
|
<h2>Prepared Statement Scan Status Opcodes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_SCANSTAT_NLOOP 0
|
|
#define SQLITE_SCANSTAT_NVISIT 1
|
|
#define SQLITE_SCANSTAT_EST 2
|
|
#define SQLITE_SCANSTAT_NAME 3
|
|
#define SQLITE_SCANSTAT_EXPLAIN 4
|
|
#define SQLITE_SCANSTAT_SELECTID 5
|
|
</pre></blockquote>
|
|
<p>
|
|
The following constants can be used for the T parameter to the
|
|
<a href="#sqlite3_stmt_scanstatus">sqlite3_stmt_scanstatus(S,X,T,V)</a> interface. Each constant designates a
|
|
different metric for sqlite3_stmt_scanstatus() to return.</p>
|
|
|
|
<p>When the value returned to V is a string, space to hold that string is
|
|
managed by the prepared statement S and will be automatically freed when
|
|
S is finalized.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitescanstatnloop"></a>
|
|
<dt>SQLITE_SCANSTAT_NLOOP</dt>
|
|
<dd>The <a href="#sqlite3_int64">sqlite3_int64</a> variable pointed to by the V parameter will be
|
|
set to the total number of times that the X-th loop has run.</dd></p>
|
|
|
|
<p><a name="sqlitescanstatnvisit"></a>
|
|
<dt>SQLITE_SCANSTAT_NVISIT</dt>
|
|
<dd>The <a href="#sqlite3_int64">sqlite3_int64</a> variable pointed to by the V parameter will be set
|
|
to the total number of rows examined by all iterations of the X-th loop.</dd></p>
|
|
|
|
<p><a name="sqlitescanstatest"></a>
|
|
<dt>SQLITE_SCANSTAT_EST</dt>
|
|
<dd>The "double" variable pointed to by the V parameter will be set to the
|
|
query planner's estimate for the average number of rows output from each
|
|
iteration of the X-th loop. If the query planner's estimates was accurate,
|
|
then this value will approximate the quotient NVISIT/NLOOP and the
|
|
product of this value for all prior loops with the same SELECTID will
|
|
be the NLOOP value for the current loop.</p>
|
|
|
|
<p><a name="sqlitescanstatname"></a>
|
|
<dt>SQLITE_SCANSTAT_NAME</dt>
|
|
<dd>The "const char *" variable pointed to by the V parameter will be set
|
|
to a zero-terminated UTF-8 string containing the name of the index or table
|
|
used for the X-th loop.</p>
|
|
|
|
<p><a name="sqlitescanstatexplain"></a>
|
|
<dt>SQLITE_SCANSTAT_EXPLAIN</dt>
|
|
<dd>The "const char *" variable pointed to by the V parameter will be set
|
|
to a zero-terminated UTF-8 string containing the <a href="eqp.html">EXPLAIN QUERY PLAN</a>
|
|
description for the X-th loop.</p>
|
|
|
|
<p><a name="sqlitescanstatselectid"></a>
|
|
<dt>SQLITE_SCANSTAT_SELECT</dt>
|
|
<dd>The "int" variable pointed to by the V parameter will be set to the
|
|
"select-id" for the X-th loop. The select-id identifies which query or
|
|
subquery the loop is part of. The main query has a select-id of zero.
|
|
The select-id is the same value as is output in the first column
|
|
of an <a href="eqp.html">EXPLAIN QUERY PLAN</a> query.
|
|
</dl>
|
|
</p><hr><a name="SQLITE_SHM_EXCLUSIVE"></a>
|
|
<h2>Flags for the xShmLock VFS method</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_SHM_UNLOCK 1
|
|
#define SQLITE_SHM_LOCK 2
|
|
#define SQLITE_SHM_SHARED 4
|
|
#define SQLITE_SHM_EXCLUSIVE 8
|
|
</pre></blockquote>
|
|
<p>
|
|
These integer constants define the various locking operations
|
|
allowed by the xShmLock method of <a href="#sqlite3_io_methods">sqlite3_io_methods</a>. The
|
|
following are the only legal combinations of flags to the
|
|
xShmLock method:</p>
|
|
|
|
<p><ul>
|
|
<li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
|
|
<li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
|
|
<li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
|
|
<li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
|
|
</ul></p>
|
|
|
|
<p>When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
|
|
was given on the corresponding lock.</p>
|
|
|
|
<p>The xShmLock method can transition between unlocked and SHARED or
|
|
between unlocked and EXCLUSIVE. It cannot transition between SHARED
|
|
and EXCLUSIVE.
|
|
</p><hr><a name="SQLITE_SOURCE_ID"></a>
|
|
<h2>Compile-Time Library Version Numbers</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_VERSION "3.33.0"
|
|
#define SQLITE_VERSION_NUMBER 3033000
|
|
#define SQLITE_SOURCE_ID "2020-08-14 13:23:32 fca8dc8b578f215a969cd899336378966156154710873e68b3d9ac5881b0ff3f"
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION</a> C preprocessor macro in the sqlite3.h header
|
|
evaluates to a string literal that is the SQLite version in the
|
|
format "X.Y.Z" where X is the major version number (always 3 for
|
|
SQLite3) and Y is the minor version number and Z is the release number.
|
|
The <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION_NUMBER</a> C preprocessor macro resolves to an integer
|
|
with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
|
|
numbers used in <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION</a>.
|
|
The SQLITE_VERSION_NUMBER for any given release of SQLite will also
|
|
be larger than the release from which it is derived. Either Y will
|
|
be held constant and Z will be incremented or else Y will be incremented
|
|
and Z will be reset to zero.</p>
|
|
|
|
<p>Since <a href="releaselog/3_6_18.html">version 3.6.18</a> (2009-09-11),
|
|
SQLite source code has been stored in the
|
|
<a href="http://www.fossil-scm.org/">Fossil configuration management
|
|
system</a>. The SQLITE_SOURCE_ID macro evaluates to
|
|
a string which identifies a particular check-in of SQLite
|
|
within its configuration management system. The SQLITE_SOURCE_ID
|
|
string contains the date and time of the check-in (UTC) and a SHA1
|
|
or SHA3-256 hash of the entire source tree. If the source code has
|
|
been edited in any way since it was last checked in, then the last
|
|
four hexadecimal digits of the hash may be modified.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_libversion">sqlite3_libversion()</a>,
|
|
<a href="#sqlite3_libversion">sqlite3_libversion_number()</a>, <a href="#sqlite3_libversion">sqlite3_sourceid()</a>,
|
|
<a href="lang_corefunc.html#sqlite_version">sqlite_version()</a> and <a href="lang_corefunc.html#sqlite_source_id">sqlite_source_id()</a>.
|
|
</p><hr><a name="SQLITE_STATIC"></a>
|
|
<h2>Constants Defining Special Destructor Behavior</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef void (*sqlite3_destructor_type)(void*);
|
|
#define SQLITE_STATIC ((sqlite3_destructor_type)0)
|
|
#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1)
|
|
</pre></blockquote>
|
|
<p>
|
|
These are special values for the destructor that is passed in as the
|
|
final argument to routines like <a href="#sqlite3_result_blob">sqlite3_result_blob()</a>. If the destructor
|
|
argument is SQLITE_STATIC, it means that the content pointer is constant
|
|
and will never change. It does not need to be destroyed. The
|
|
SQLITE_TRANSIENT value means that the content will likely change in
|
|
the near future and that SQLite should make its own private copy of
|
|
the content before returning.</p>
|
|
|
|
<p>The typedef is necessary to work around problems in certain
|
|
C++ compilers.
|
|
</p><hr><a name="SQLITE_STATUS_MALLOC_COUNT"></a>
|
|
<h2>Status Parameters</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_STATUS_MEMORY_USED 0
|
|
#define SQLITE_STATUS_PAGECACHE_USED 1
|
|
#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2
|
|
#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */
|
|
#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */
|
|
#define SQLITE_STATUS_MALLOC_SIZE 5
|
|
#define SQLITE_STATUS_PARSER_STACK 6
|
|
#define SQLITE_STATUS_PAGECACHE_SIZE 7
|
|
#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */
|
|
#define SQLITE_STATUS_MALLOC_COUNT 9
|
|
</pre></blockquote>
|
|
<p>
|
|
These integer constants designate various run-time status parameters
|
|
that can be returned by <a href="#sqlite3_status">sqlite3_status()</a>.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitestatusmemoryused"></a>
|
|
<dt>SQLITE_STATUS_MEMORY_USED</dt>
|
|
<dd>This parameter is the current amount of memory checked out
|
|
using <a href="#sqlite3_free">sqlite3_malloc()</a>, either directly or indirectly. The
|
|
figure includes calls made to <a href="#sqlite3_free">sqlite3_malloc()</a> by the application
|
|
and internal memory usage by the SQLite library. Auxiliary page-cache
|
|
memory controlled by <a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a> is not included in
|
|
this parameter. The amount returned is the sum of the allocation
|
|
sizes as reported by the xSize method in <a href="#sqlite3_mem_methods">sqlite3_mem_methods</a>.</dd></p>
|
|
|
|
<p><a name="sqlitestatusmallocsize"></a>
|
|
<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
|
|
<dd>This parameter records the largest memory allocation request
|
|
handed to <a href="#sqlite3_free">sqlite3_malloc()</a> or <a href="#sqlite3_free">sqlite3_realloc()</a> (or their
|
|
internal equivalents). Only the value returned in the
|
|
*pHighwater parameter to <a href="#sqlite3_status">sqlite3_status()</a> is of interest.
|
|
The value written into the *pCurrent parameter is undefined.</dd></p>
|
|
|
|
<p><a name="sqlitestatusmalloccount"></a>
|
|
<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
|
|
<dd>This parameter records the number of separate memory allocations
|
|
currently checked out.</dd></p>
|
|
|
|
<p><a name="sqlitestatuspagecacheused"></a>
|
|
<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
|
|
<dd>This parameter returns the number of pages used out of the
|
|
<a href="malloc.html#pagecache">pagecache memory allocator</a> that was configured using
|
|
<a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>. The
|
|
value returned is in pages, not in bytes.</dd></p>
|
|
|
|
<p><a name="sqlitestatuspagecacheoverflow"></a>
|
|
|
|
<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
|
|
<dd>This parameter returns the number of bytes of page cache
|
|
allocation which could not be satisfied by the <a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>
|
|
buffer and where forced to overflow to <a href="#sqlite3_free">sqlite3_malloc()</a>. The
|
|
returned value includes allocations that overflowed because they
|
|
where too large (they were larger than the "sz" parameter to
|
|
<a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>) and allocations that overflowed because
|
|
no space was left in the page cache.</dd></p>
|
|
|
|
<p><a name="sqlitestatuspagecachesize"></a>
|
|
<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
|
|
<dd>This parameter records the largest memory allocation request
|
|
handed to the <a href="malloc.html#pagecache">pagecache memory allocator</a>. Only the value returned in the
|
|
*pHighwater parameter to <a href="#sqlite3_status">sqlite3_status()</a> is of interest.
|
|
The value written into the *pCurrent parameter is undefined.</dd></p>
|
|
|
|
<p><a name="sqlitestatusscratchused"></a>
|
|
<dt>SQLITE_STATUS_SCRATCH_USED</dt>
|
|
<dd>No longer used.</dd></p>
|
|
|
|
<p><a name="sqlitestatusscratchoverflow"></a>
|
|
<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
|
|
<dd>No longer used.</dd></p>
|
|
|
|
<p><a name="sqlitestatusscratchsize"></a>
|
|
<dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
|
|
<dd>No longer used.</dd></p>
|
|
|
|
<p><a name="sqlitestatusparserstack"></a>
|
|
<dt>SQLITE_STATUS_PARSER_STACK</dt>
|
|
<dd>The *pHighwater parameter records the deepest parser stack.
|
|
The *pCurrent value is undefined. The *pHighwater value is only
|
|
meaningful if SQLite is compiled with <a href="compile.html#yytrackmaxstackdepth">YYTRACKMAXSTACKDEPTH</a>.</dd>
|
|
</dl></p>
|
|
|
|
<p>New status parameters may be added from time to time.
|
|
</p><hr><a name="SQLITE_SYNC_DATAONLY"></a>
|
|
<h2>Synchronization Type Flags</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_SYNC_NORMAL 0x00002
|
|
#define SQLITE_SYNC_FULL 0x00003
|
|
#define SQLITE_SYNC_DATAONLY 0x00010
|
|
</pre></blockquote>
|
|
<p>
|
|
When SQLite invokes the xSync() method of an
|
|
<a href="#sqlite3_io_methods">sqlite3_io_methods</a> object it uses a combination of
|
|
these integer values as the second argument.</p>
|
|
|
|
<p>When the SQLITE_SYNC_DATAONLY flag is used, it means that the
|
|
sync operation only needs to flush data to mass storage. Inode
|
|
information need not be flushed. If the lower four bits of the flag
|
|
equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
|
|
If the lower four bits equal SQLITE_SYNC_FULL, that means
|
|
to use Mac OS X style fullsync instead of fsync().</p>
|
|
|
|
<p>Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
|
|
with the <a href="pragma.html#pragma_synchronous">PRAGMA synchronous</a>=NORMAL and <a href="pragma.html#pragma_synchronous">PRAGMA synchronous</a>=FULL
|
|
settings. The <a href="pragma.html#pragma_synchronous">synchronous pragma</a> determines when calls to the
|
|
xSync VFS method occur and applies uniformly across all platforms.
|
|
The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
|
|
energetic or rigorous or forceful the sync operations are and
|
|
only make a difference on Mac OSX for the default SQLite code.
|
|
(Third-party VFS implementations might also make the distinction
|
|
between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
|
|
operating systems natively supported by SQLite, only Mac OSX
|
|
cares about the difference.)
|
|
</p><hr><a name="SQLITE_TESTCTRL_ALWAYS"></a>
|
|
<h2>Testing Interface Operation Codes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_TESTCTRL_FIRST 5
|
|
#define SQLITE_TESTCTRL_PRNG_SAVE 5
|
|
#define SQLITE_TESTCTRL_PRNG_RESTORE 6
|
|
#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */
|
|
#define SQLITE_TESTCTRL_BITVEC_TEST 8
|
|
#define SQLITE_TESTCTRL_FAULT_INSTALL 9
|
|
#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10
|
|
#define SQLITE_TESTCTRL_PENDING_BYTE 11
|
|
#define SQLITE_TESTCTRL_ASSERT 12
|
|
#define SQLITE_TESTCTRL_ALWAYS 13
|
|
#define SQLITE_TESTCTRL_RESERVE 14 /* NOT USED */
|
|
#define SQLITE_TESTCTRL_OPTIMIZATIONS 15
|
|
#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */
|
|
#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */
|
|
#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17
|
|
#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18
|
|
#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */
|
|
#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19
|
|
#define SQLITE_TESTCTRL_NEVER_CORRUPT 20
|
|
#define SQLITE_TESTCTRL_VDBE_COVERAGE 21
|
|
#define SQLITE_TESTCTRL_BYTEORDER 22
|
|
#define SQLITE_TESTCTRL_ISINIT 23
|
|
#define SQLITE_TESTCTRL_SORTER_MMAP 24
|
|
#define SQLITE_TESTCTRL_IMPOSTER 25
|
|
#define SQLITE_TESTCTRL_PARSER_COVERAGE 26
|
|
#define SQLITE_TESTCTRL_RESULT_INTREAL 27
|
|
#define SQLITE_TESTCTRL_PRNG_SEED 28
|
|
#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29
|
|
#define SQLITE_TESTCTRL_LAST 29 /* Largest TESTCTRL */
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants are the valid operation code parameters used
|
|
as the first argument to <a href="#sqlite3_test_control">sqlite3_test_control()</a>.</p>
|
|
|
|
<p>These parameters and their meanings are subject to change
|
|
without notice. These values are for testing purposes only.
|
|
Applications should not use any of these parameters or the
|
|
<a href="#sqlite3_test_control">sqlite3_test_control()</a> interface.
|
|
</p><hr><a name="SQLITE_TRACE"></a>
|
|
<h2>SQL Trace Event Codes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_TRACE_STMT 0x01
|
|
#define SQLITE_TRACE_PROFILE 0x02
|
|
#define SQLITE_TRACE_ROW 0x04
|
|
#define SQLITE_TRACE_CLOSE 0x08
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants identify classes of events that can be monitored
|
|
using the <a href="#sqlite3_trace_v2">sqlite3_trace_v2()</a> tracing logic. The M argument
|
|
to <a href="#sqlite3_trace_v2">sqlite3_trace_v2(D,M,X,P)</a> is an OR-ed combination of one or more of
|
|
the following constants. The first argument to the trace callback
|
|
is one of the following constants.</p>
|
|
|
|
<p>New tracing constants may be added in future releases.</p>
|
|
|
|
<p>A trace callback has four arguments: xCallback(T,C,P,X).
|
|
The T argument is one of the integer type codes above.
|
|
The C argument is a copy of the context pointer passed in as the
|
|
fourth argument to <a href="#sqlite3_trace_v2">sqlite3_trace_v2()</a>.
|
|
The P and X arguments are pointers whose meanings depend on T.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitetracestmt"></a>
|
|
<dt>SQLITE_TRACE_STMT</dt>
|
|
<dd>An SQLITE_TRACE_STMT callback is invoked when a prepared statement
|
|
first begins running and possibly at other times during the
|
|
execution of the prepared statement, such as at the start of each
|
|
trigger subprogram. The P argument is a pointer to the
|
|
<a href="#sqlite3_stmt">prepared statement</a>. The X argument is a pointer to a string which
|
|
is the unexpanded SQL text of the prepared statement or an SQL comment
|
|
that indicates the invocation of a trigger. The callback can compute
|
|
the same text that would have been returned by the legacy <a href="#sqlite3_profile">sqlite3_trace()</a>
|
|
interface by using the X argument when X begins with "--" and invoking
|
|
<a href="#sqlite3_expanded_sql">sqlite3_expanded_sql(P)</a> otherwise.</p>
|
|
|
|
<p><a name="sqlitetraceprofile"></a>
|
|
<dt>SQLITE_TRACE_PROFILE</dt>
|
|
<dd>An SQLITE_TRACE_PROFILE callback provides approximately the same
|
|
information as is provided by the <a href="#sqlite3_profile">sqlite3_profile()</a> callback.
|
|
The P argument is a pointer to the <a href="#sqlite3_stmt">prepared statement</a> and the
|
|
X argument points to a 64-bit integer which is the estimated of
|
|
the number of nanosecond that the prepared statement took to run.
|
|
The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.</p>
|
|
|
|
<p><a name="sqlitetracerow"></a>
|
|
<dt>SQLITE_TRACE_ROW</dt>
|
|
<dd>An SQLITE_TRACE_ROW callback is invoked whenever a prepared
|
|
statement generates a single row of result.
|
|
The P argument is a pointer to the <a href="#sqlite3_stmt">prepared statement</a> and the
|
|
X argument is unused.</p>
|
|
|
|
<p><a name="sqlitetraceclose"></a>
|
|
<dt>SQLITE_TRACE_CLOSE</dt>
|
|
<dd>An SQLITE_TRACE_CLOSE callback is invoked when a database
|
|
connection closes.
|
|
The P argument is a pointer to the <a href="#sqlite3">database connection</a> object
|
|
and the X argument is unused.
|
|
</dl>
|
|
</p><hr><a name="SQLITE_VTAB_CONSTRAINT_SUPPORT"></a>
|
|
<h2>Virtual Table Configuration Options</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
|
|
#define SQLITE_VTAB_INNOCUOUS 2
|
|
#define SQLITE_VTAB_DIRECTONLY 3
|
|
</pre></blockquote>
|
|
<p>
|
|
These macros define the various options to the
|
|
<a href="#sqlite3_vtab_config">sqlite3_vtab_config()</a> interface that <a href="vtab.html">virtual table</a> implementations
|
|
can use to customize and optimize their behavior.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitevtabconstraintsupport"></a>
|
|
|
|
<dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
|
|
<dd>Calls of the form
|
|
<a href="#sqlite3_vtab_config">sqlite3_vtab_config</a>(db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
|
|
where X is an integer. If X is zero, then the <a href="vtab.html">virtual table</a> whose
|
|
<a href="vtab.html#xcreate">xCreate</a> or <a href="vtab.html#xconnect">xConnect</a> method invoked <a href="#sqlite3_vtab_config">sqlite3_vtab_config()</a> does not
|
|
support constraints. In this configuration (which is the default) if
|
|
a call to the <a href="vtab.html#xupdate">xUpdate</a> method returns <a href="#SQLITE_ABORT">SQLITE_CONSTRAINT</a>, then the entire
|
|
statement is rolled back as if <a href="lang_conflict.html">OR ABORT</a> had been
|
|
specified as part of the users SQL statement, regardless of the actual
|
|
ON CONFLICT mode specified.</p>
|
|
|
|
<p>If X is non-zero, then the virtual table implementation guarantees
|
|
that if <a href="vtab.html#xupdate">xUpdate</a> returns <a href="#SQLITE_ABORT">SQLITE_CONSTRAINT</a>, it will do so before
|
|
any modifications to internal or persistent data structures have been made.
|
|
If the <a href="lang_conflict.html">ON CONFLICT</a> mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
|
|
is able to roll back a statement or database transaction, and abandon
|
|
or continue processing the current SQL statement as appropriate.
|
|
If the ON CONFLICT mode is REPLACE and the <a href="vtab.html#xupdate">xUpdate</a> method returns
|
|
<a href="#SQLITE_ABORT">SQLITE_CONSTRAINT</a>, SQLite handles this as if the ON CONFLICT mode
|
|
had been ABORT.</p>
|
|
|
|
<p>Virtual table implementations that are required to handle OR REPLACE
|
|
must do so within the <a href="vtab.html#xupdate">xUpdate</a> method. If a call to the
|
|
<a href="#sqlite3_vtab_on_conflict">sqlite3_vtab_on_conflict()</a> function indicates that the current ON
|
|
CONFLICT policy is REPLACE, the virtual table implementation should
|
|
silently replace the appropriate rows within the xUpdate callback and
|
|
return SQLITE_OK. Or, if this is not possible, it may return
|
|
SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
|
|
constraint handling.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitevtabdirectonly"></a>
|
|
<dt>SQLITE_VTAB_DIRECTONLY</dt>
|
|
<dd>Calls of the form
|
|
<a href="#sqlite3_vtab_config">sqlite3_vtab_config</a>(db,SQLITE_VTAB_DIRECTONLY) from within the
|
|
the <a href="vtab.html#xconnect">xConnect</a> or <a href="vtab.html#xcreate">xCreate</a> methods of a <a href="vtab.html">virtual table</a> implmentation
|
|
prohibits that virtual table from being used from within triggers and
|
|
views.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitevtabinnocuous"></a>
|
|
<dt>SQLITE_VTAB_INNOCUOUS</dt>
|
|
<dd>Calls of the form
|
|
<a href="#sqlite3_vtab_config">sqlite3_vtab_config</a>(db,SQLITE_VTAB_INNOCUOUS) from within the
|
|
the <a href="vtab.html#xconnect">xConnect</a> or <a href="vtab.html#xcreate">xCreate</a> methods of a <a href="vtab.html">virtual table</a> implmentation
|
|
identify that virtual table as being safe to use from within triggers
|
|
and views. Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
|
|
virtual table can do no serious harm even if it is controlled by a
|
|
malicious hacker. Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
|
|
flag unless absolutely necessary.
|
|
</dd>
|
|
</dl>
|
|
</p><hr><a name="SQLITE_WIN32_DATA_DIRECTORY_TYPE"></a>
|
|
<h2>Win32 Directory Types</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1
|
|
#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2
|
|
</pre></blockquote>
|
|
<p>
|
|
These macros are only available on Windows. They define the allowed values
|
|
for the type argument to the <a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory</a> interface.
|
|
</p><hr><a name="SQLITE_LIMIT_ATTACHED"></a>
|
|
<h2>Run-Time Limit Categories</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_LIMIT_LENGTH 0
|
|
#define SQLITE_LIMIT_SQL_LENGTH 1
|
|
#define SQLITE_LIMIT_COLUMN 2
|
|
#define SQLITE_LIMIT_EXPR_DEPTH 3
|
|
#define SQLITE_LIMIT_COMPOUND_SELECT 4
|
|
#define SQLITE_LIMIT_VDBE_OP 5
|
|
#define SQLITE_LIMIT_FUNCTION_ARG 6
|
|
#define SQLITE_LIMIT_ATTACHED 7
|
|
#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8
|
|
#define SQLITE_LIMIT_VARIABLE_NUMBER 9
|
|
#define SQLITE_LIMIT_TRIGGER_DEPTH 10
|
|
#define SQLITE_LIMIT_WORKER_THREADS 11
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants define various performance limits
|
|
that can be lowered at run-time using <a href="#sqlite3_limit">sqlite3_limit()</a>.
|
|
The synopsis of the meanings of the various limits is shown below.
|
|
Additional information is available at <a href="limits.html">Limits in SQLite</a>.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitelimitlength"></a>
|
|
<dt>SQLITE_LIMIT_LENGTH</dt>
|
|
<dd>The maximum size of any string or BLOB or table row, in bytes.<dd></p>
|
|
|
|
<p><a name="sqlitelimitsqllength"></a>
|
|
<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
|
|
<dd>The maximum length of an SQL statement, in bytes.</dd></p>
|
|
|
|
<p><a name="sqlitelimitcolumn"></a>
|
|
<dt>SQLITE_LIMIT_COLUMN</dt>
|
|
<dd>The maximum number of columns in a table definition or in the
|
|
result set of a <a href="lang_select.html">SELECT</a> or the maximum number of columns in an index
|
|
or in an ORDER BY or GROUP BY clause.</dd></p>
|
|
|
|
<p><a name="sqlitelimitexprdepth"></a>
|
|
<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
|
|
<dd>The maximum depth of the parse tree on any expression.</dd></p>
|
|
|
|
<p><a name="sqlitelimitcompoundselect"></a>
|
|
<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
|
|
<dd>The maximum number of terms in a compound SELECT statement.</dd></p>
|
|
|
|
<p><a name="sqlitelimitvdbeop"></a>
|
|
<dt>SQLITE_LIMIT_VDBE_OP</dt>
|
|
<dd>The maximum number of instructions in a virtual machine program
|
|
used to implement an SQL statement. If <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or
|
|
the equivalent tries to allocate space for more than this many opcodes
|
|
in a single prepared statement, an SQLITE_NOMEM error is returned.</dd></p>
|
|
|
|
<p><a name="sqlitelimitfunctionarg"></a>
|
|
<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
|
|
<dd>The maximum number of arguments on a function.</dd></p>
|
|
|
|
<p><a name="sqlitelimitattached"></a>
|
|
<dt>SQLITE_LIMIT_ATTACHED</dt>
|
|
<dd>The maximum number of <a href="lang_attach.html">attached databases</a>.</dd></p>
|
|
|
|
<p><a name="sqlitelimitlikepatternlength"></a>
|
|
|
|
<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
|
|
<dd>The maximum length of the pattern argument to the <a href="lang_expr.html#like">LIKE</a> or
|
|
<a href="lang_expr.html#glob">GLOB</a> operators.</dd></p>
|
|
|
|
<p><a name="sqlitelimitvariablenumber"></a>
|
|
|
|
<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
|
|
<dd>The maximum index number of any <a href="lang_expr.html#varparam">parameter</a> in an SQL statement.</p>
|
|
|
|
<p><a name="sqlitelimittriggerdepth"></a>
|
|
<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
|
|
<dd>The maximum depth of recursion for triggers.</dd></p>
|
|
|
|
<p><a name="sqlitelimitworkerthreads"></a>
|
|
<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
|
|
<dd>The maximum number of auxiliary worker threads that a single
|
|
<a href="#sqlite3_stmt">prepared statement</a> may start.</dd>
|
|
</dl>
|
|
</p><hr><a name="SQLITE_DBSTATUS options"></a>
|
|
<h2>Status Parameters for database connections</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_DBSTATUS_LOOKASIDE_USED 0
|
|
#define SQLITE_DBSTATUS_CACHE_USED 1
|
|
#define SQLITE_DBSTATUS_SCHEMA_USED 2
|
|
#define SQLITE_DBSTATUS_STMT_USED 3
|
|
#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4
|
|
#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5
|
|
#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6
|
|
#define SQLITE_DBSTATUS_CACHE_HIT 7
|
|
#define SQLITE_DBSTATUS_CACHE_MISS 8
|
|
#define SQLITE_DBSTATUS_CACHE_WRITE 9
|
|
#define SQLITE_DBSTATUS_DEFERRED_FKS 10
|
|
#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11
|
|
#define SQLITE_DBSTATUS_CACHE_SPILL 12
|
|
#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */
|
|
</pre></blockquote>
|
|
<p>
|
|
These constants are the available integer "verbs" that can be passed as
|
|
the second argument to the <a href="#sqlite3_db_status">sqlite3_db_status()</a> interface.</p>
|
|
|
|
<p>New verbs may be added in future releases of SQLite. Existing verbs
|
|
might be discontinued. Applications should check the return code from
|
|
<a href="#sqlite3_db_status">sqlite3_db_status()</a> to make sure that the call worked.
|
|
The <a href="#sqlite3_db_status">sqlite3_db_status()</a> interface will return a non-zero error code
|
|
if a discontinued or unsupported verb is invoked.</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitedbstatuslookasideused"></a>
|
|
<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
|
|
<dd>This parameter returns the number of lookaside memory slots currently
|
|
checked out.</dd></p>
|
|
|
|
<p><a name="sqlitedbstatuslookasidehit"></a>
|
|
<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
|
|
<dd>This parameter returns the number of malloc attempts that were
|
|
satisfied using lookaside memory. Only the high-water value is meaningful;
|
|
the current value is always zero.</p>
|
|
|
|
<p><a name="sqlitedbstatuslookasidemisssize"></a>
|
|
|
|
<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
|
|
<dd>This parameter returns the number malloc attempts that might have
|
|
been satisfied using lookaside memory but failed due to the amount of
|
|
memory requested being larger than the lookaside slot size.
|
|
Only the high-water value is meaningful;
|
|
the current value is always zero.</p>
|
|
|
|
<p><a name="sqlitedbstatuslookasidemissfull"></a>
|
|
|
|
<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
|
|
<dd>This parameter returns the number malloc attempts that might have
|
|
been satisfied using lookaside memory but failed due to all lookaside
|
|
memory already being in use.
|
|
Only the high-water value is meaningful;
|
|
the current value is always zero.</p>
|
|
|
|
<p><a name="sqlitedbstatuscacheused"></a>
|
|
<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
|
|
<dd>This parameter returns the approximate number of bytes of heap
|
|
memory used by all pager caches associated with the database connection.
|
|
The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.</p>
|
|
|
|
<p><a name="sqlitedbstatuscacheusedshared"></a>
|
|
|
|
<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
|
|
<dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
|
|
pager cache is shared between two or more connections the bytes of heap
|
|
memory used by that pager cache is divided evenly between the attached
|
|
connections. In other words, if none of the pager caches associated
|
|
with the database connection are shared, this request returns the same
|
|
value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
|
|
shared, the value returned by this call will be smaller than that returned
|
|
by DBSTATUS_CACHE_USED. The highwater mark associated with
|
|
SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.</p>
|
|
|
|
<p><a name="sqlitedbstatusschemaused"></a>
|
|
<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
|
|
<dd>This parameter returns the approximate number of bytes of heap
|
|
memory used to store the schema for all databases associated
|
|
with the connection - main, temp, and any <a href="lang_attach.html">ATTACH</a>-ed databases.
|
|
The full amount of memory used by the schemas is reported, even if the
|
|
schema memory is shared with other database connections due to
|
|
<a href="sharedcache.html">shared cache mode</a> being enabled.
|
|
The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.</p>
|
|
|
|
<p><a name="sqlitedbstatusstmtused"></a>
|
|
<dt>SQLITE_DBSTATUS_STMT_USED</dt>
|
|
<dd>This parameter returns the approximate number of bytes of heap
|
|
and lookaside memory used by all prepared statements associated with
|
|
the database connection.
|
|
The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbstatuscachehit"></a>
|
|
<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
|
|
<dd>This parameter returns the number of pager cache hits that have
|
|
occurred. The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
|
|
is always 0.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbstatuscachemiss"></a>
|
|
<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
|
|
<dd>This parameter returns the number of pager cache misses that have
|
|
occurred. The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
|
|
is always 0.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbstatuscachewrite"></a>
|
|
<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
|
|
<dd>This parameter returns the number of dirty cache entries that have
|
|
been written to disk. Specifically, the number of pages written to the
|
|
wal file in wal mode databases, or the number of pages written to the
|
|
database file in rollback mode databases. Any pages written as part of
|
|
transaction rollback or database recovery operations are not included.
|
|
If an IO or other error occurs while writing a page to disk, the effect
|
|
on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined. The
|
|
highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbstatuscachespill"></a>
|
|
<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
|
|
<dd>This parameter returns the number of dirty cache entries that have
|
|
been written to disk in the middle of a transaction due to the page
|
|
cache overflowing. Transactions are more efficient if they are written
|
|
to disk all at once. When pages spill mid-transaction, that introduces
|
|
additional overhead. This parameter can be used help identify
|
|
inefficiencies that can be resolved by increasing the cache size.
|
|
</dd></p>
|
|
|
|
<p><a name="sqlitedbstatusdeferredfks"></a>
|
|
<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
|
|
<dd>This parameter returns zero for the current value if and only if
|
|
all foreign key constraints (deferred or immediate) have been
|
|
resolved. The highwater mark is always 0.
|
|
</dd>
|
|
</dl>
|
|
</p><hr><a name="SQLITE_STMTSTATUS counter"></a>
|
|
<h2>Status Parameters for prepared statements</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1
|
|
#define SQLITE_STMTSTATUS_SORT 2
|
|
#define SQLITE_STMTSTATUS_AUTOINDEX 3
|
|
#define SQLITE_STMTSTATUS_VM_STEP 4
|
|
#define SQLITE_STMTSTATUS_REPREPARE 5
|
|
#define SQLITE_STMTSTATUS_RUN 6
|
|
#define SQLITE_STMTSTATUS_MEMUSED 99
|
|
</pre></blockquote>
|
|
<p>
|
|
These preprocessor macros define integer codes that name counter
|
|
values associated with the <a href="#sqlite3_stmt_status">sqlite3_stmt_status()</a> interface.
|
|
The meanings of the various counters are as follows:</p>
|
|
|
|
<p><dl>
|
|
<a name="sqlitestmtstatusfullscanstep"></a>
|
|
<dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
|
|
<dd>This is the number of times that SQLite has stepped forward in
|
|
a table as part of a full table scan. Large numbers for this counter
|
|
may indicate opportunities for performance improvement through
|
|
careful use of indices.</dd></p>
|
|
|
|
<p><a name="sqlitestmtstatussort"></a>
|
|
<dt>SQLITE_STMTSTATUS_SORT</dt>
|
|
<dd>This is the number of sort operations that have occurred.
|
|
A non-zero value in this counter may indicate an opportunity to
|
|
improvement performance through careful use of indices.</dd></p>
|
|
|
|
<p><a name="sqlitestmtstatusautoindex"></a>
|
|
<dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
|
|
<dd>This is the number of rows inserted into transient indices that
|
|
were created automatically in order to help joins run faster.
|
|
A non-zero value in this counter may indicate an opportunity to
|
|
improvement performance by adding permanent indices that do not
|
|
need to be reinitialized each time the statement is run.</dd></p>
|
|
|
|
<p><a name="sqlitestmtstatusvmstep"></a>
|
|
<dt>SQLITE_STMTSTATUS_VM_STEP</dt>
|
|
<dd>This is the number of virtual machine operations executed
|
|
by the prepared statement if that number is less than or equal
|
|
to 2147483647. The number of virtual machine operations can be
|
|
used as a proxy for the total work done by the prepared statement.
|
|
If the number of virtual machine operations exceeds 2147483647
|
|
then the value returned by this statement status code is undefined.</p>
|
|
|
|
<p><a name="sqlitestmtstatusreprepare"></a>
|
|
<dt>SQLITE_STMTSTATUS_REPREPARE</dt>
|
|
<dd>This is the number of times that the prepare statement has been
|
|
automatically regenerated due to schema changes or changes to
|
|
<a href="lang_expr.html#varparam">bound parameters</a> that might affect the query plan.</p>
|
|
|
|
<p><a name="sqlitestmtstatusrun"></a>
|
|
<dt>SQLITE_STMTSTATUS_RUN</dt>
|
|
<dd>This is the number of times that the prepared statement has
|
|
been run. A single "run" for the purposes of this counter is one
|
|
or more calls to <a href="#sqlite3_step">sqlite3_step()</a> followed by a call to <a href="#sqlite3_reset">sqlite3_reset()</a>.
|
|
The counter is incremented on the first <a href="#sqlite3_step">sqlite3_step()</a> call of each
|
|
cycle.</p>
|
|
|
|
<p><a name="sqlitestmtstatusmemused"></a>
|
|
<dt>SQLITE_STMTSTATUS_MEMUSED</dt>
|
|
<dd>This is the approximate number of bytes of heap memory
|
|
used to store the prepared statement. This value is not actually
|
|
a counter, and so the resetFlg parameter to sqlite3_stmt_status()
|
|
is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
|
|
</dd>
|
|
</dl>
|
|
</p><hr><a name="sqlite3_int64"></a>
|
|
<h2>64-Bit Integer Types</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#ifdef SQLITE_INT64_TYPE
|
|
typedef SQLITE_INT64_TYPE sqlite_int64;
|
|
# ifdef SQLITE_UINT64_TYPE
|
|
typedef SQLITE_UINT64_TYPE sqlite_uint64;
|
|
# else
|
|
typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
|
|
# endif
|
|
#elif defined(_MSC_VER) || defined(__BORLANDC__)
|
|
typedef __int64 sqlite_int64;
|
|
typedef unsigned __int64 sqlite_uint64;
|
|
#else
|
|
typedef long long int sqlite_int64;
|
|
typedef unsigned long long int sqlite_uint64;
|
|
#endif
|
|
typedef sqlite_int64 sqlite3_int64;
|
|
typedef sqlite_uint64 sqlite3_uint64;
|
|
</pre></blockquote>
|
|
<p>
|
|
Because there is no cross-platform way to specify 64-bit integer types
|
|
SQLite includes typedefs for 64-bit signed and unsigned integers.</p>
|
|
|
|
<p>The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
|
|
The sqlite_int64 and sqlite_uint64 types are supported for backwards
|
|
compatibility only.</p>
|
|
|
|
<p>The sqlite3_int64 and sqlite_int64 types can store integer values
|
|
between -9223372036854775808 and +9223372036854775807 inclusive. The
|
|
sqlite3_uint64 and sqlite_uint64 types can store integer values
|
|
between 0 and +18446744073709551615 inclusive.
|
|
</p><hr><a name="sqlite3_module"></a>
|
|
<h2>Virtual Table Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
struct sqlite3_module {
|
|
int iVersion;
|
|
int (*xCreate)(sqlite3*, void *pAux,
|
|
int argc, const char *const*argv,
|
|
sqlite3_vtab **ppVTab, char**);
|
|
int (*xConnect)(sqlite3*, void *pAux,
|
|
int argc, const char *const*argv,
|
|
sqlite3_vtab **ppVTab, char**);
|
|
int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
|
|
int (*xDisconnect)(sqlite3_vtab *pVTab);
|
|
int (*xDestroy)(sqlite3_vtab *pVTab);
|
|
int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
|
|
int (*xClose)(sqlite3_vtab_cursor*);
|
|
int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
|
|
int argc, sqlite3_value **argv);
|
|
int (*xNext)(sqlite3_vtab_cursor*);
|
|
int (*xEof)(sqlite3_vtab_cursor*);
|
|
int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
|
|
int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
|
|
int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
|
|
int (*xBegin)(sqlite3_vtab *pVTab);
|
|
int (*xSync)(sqlite3_vtab *pVTab);
|
|
int (*xCommit)(sqlite3_vtab *pVTab);
|
|
int (*xRollback)(sqlite3_vtab *pVTab);
|
|
int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
|
|
void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
|
|
void **ppArg);
|
|
int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
|
|
/* The methods above are in version 1 of the sqlite_module object. Those
|
|
** below are for version 2 and greater. */
|
|
int (*xSavepoint)(sqlite3_vtab *pVTab, int);
|
|
int (*xRelease)(sqlite3_vtab *pVTab, int);
|
|
int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
|
|
/* The methods above are in versions 1 and 2 of the sqlite_module object.
|
|
** Those below are for version 3 and greater. */
|
|
int (*xShadowName)(const char*);
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
This structure, sometimes called a "virtual table module",
|
|
defines the implementation of a <a href="vtab.html">virtual table</a>.
|
|
This structure consists mostly of methods for the module.</p>
|
|
|
|
<p>A virtual table module is created by filling in a persistent
|
|
instance of this structure and passing a pointer to that instance
|
|
to <a href="#sqlite3_create_module">sqlite3_create_module()</a> or <a href="#sqlite3_create_module">sqlite3_create_module_v2()</a>.
|
|
The registration remains valid until it is replaced by a different
|
|
module or until the <a href="#sqlite3">database connection</a> closes. The content
|
|
of this structure must not change while it is registered with
|
|
any database connection.
|
|
</p><hr><a name="sqlite3_vtab_cursor"></a>
|
|
<h2>Virtual Table Cursor Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
struct sqlite3_vtab_cursor {
|
|
sqlite3_vtab *pVtab; /* Virtual table of this cursor */
|
|
/* Virtual table implementations will typically add additional fields */
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
Every <a href="#sqlite3_module">virtual table module</a> implementation uses a subclass of the
|
|
following structure to describe cursors that point into the
|
|
<a href="vtab.html">virtual table</a> and are used
|
|
to loop through the virtual table. Cursors are created using the
|
|
<a href="vtab.html#xopen">xOpen</a> method of the module and are destroyed
|
|
by the <a href="vtab.html#xclose">xClose</a> method. Cursors are used
|
|
by the <a href="vtab.html#xfilter">xFilter</a>, <a href="vtab.html#xnext">xNext</a>, <a href="vtab.html#xeof">xEof</a>, <a href="vtab.html#xcolumn">xColumn</a>, and <a href="vtab.html#xrowid">xRowid</a> methods
|
|
of the module. Each module implementation will define
|
|
the content of a cursor structure to suit its own needs.</p>
|
|
|
|
<p>This superclass exists in order to define fields of the cursor that
|
|
are common to all implementations.
|
|
</p><hr><a name="sqlite3_blob"></a>
|
|
<h2>A Handle To An Open BLOB</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_blob sqlite3_blob;
|
|
</pre></blockquote>
|
|
<p>
|
|
An instance of this object represents an open BLOB on which
|
|
<a href="#sqlite3_blob_open">incremental BLOB I/O</a> can be performed.
|
|
Objects of this type are created by <a href="#sqlite3_blob_open">sqlite3_blob_open()</a>
|
|
and destroyed by <a href="#sqlite3_blob_close">sqlite3_blob_close()</a>.
|
|
The <a href="#sqlite3_blob_read">sqlite3_blob_read()</a> and <a href="#sqlite3_blob_write">sqlite3_blob_write()</a> interfaces
|
|
can be used to read or write small subsections of the BLOB.
|
|
The <a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a> interface returns the size of the BLOB in bytes.
|
|
</p><p>Constructor: <a href="#sqlite3_blob_open">sqlite3_blob_open()</a></p>
|
|
<p>Destructor: <a href="#sqlite3_blob_close">sqlite3_blob_close()</a></p>
|
|
<p>Methods:
|
|
<a href="#sqlite3_blob_bytes">sqlite3_blob_bytes()</a>,
|
|
<a href="#sqlite3_blob_read">sqlite3_blob_read()</a>,
|
|
<a href="#sqlite3_blob_reopen">sqlite3_blob_reopen()</a>,
|
|
<a href="#sqlite3_blob_write">sqlite3_blob_write()</a></p>
|
|
<hr><a name="sqlite3"></a>
|
|
<h2>Database Connection Handle</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3 sqlite3;
|
|
</pre></blockquote>
|
|
<p>
|
|
Each open SQLite database is represented by a pointer to an instance of
|
|
the opaque structure named "sqlite3". It is useful to think of an sqlite3
|
|
pointer as an object. The <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open16()</a>, and
|
|
<a href="#sqlite3_open">sqlite3_open_v2()</a> interfaces are its constructors, and <a href="#sqlite3_close">sqlite3_close()</a>
|
|
and <a href="#sqlite3_close">sqlite3_close_v2()</a> are its destructors. There are many other
|
|
interfaces (such as
|
|
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_create_function">sqlite3_create_function()</a>, and
|
|
<a href="#sqlite3_busy_timeout">sqlite3_busy_timeout()</a> to name but three) that are methods on an
|
|
sqlite3 object.
|
|
</p><p>Constructors:
|
|
<a href="#sqlite3_open">sqlite3_open()</a>,
|
|
<a href="#sqlite3_open">sqlite3_open16()</a>,
|
|
<a href="#sqlite3_open">sqlite3_open_v2()</a></p>
|
|
<p>Destructors:
|
|
<a href="#sqlite3_close">sqlite3_close()</a>,
|
|
<a href="#sqlite3_close">sqlite3_close_v2()</a></p>
|
|
<div class='columns' style='columns: 17em auto;'>
|
|
<ul style='padding-top:0;'>
|
|
<li><a href='#sqlite3_blob_open'>sqlite3_blob_open</a></li>
|
|
<li><a href='#sqlite3_busy_handler'>sqlite3_busy_handler</a></li>
|
|
<li><a href='#sqlite3_busy_timeout'>sqlite3_busy_timeout</a></li>
|
|
<li><a href='#sqlite3_changes'>sqlite3_changes</a></li>
|
|
<li><a href='#sqlite3_collation_needed'>sqlite3_collation_needed</a></li>
|
|
<li><a href='#sqlite3_collation_needed'>sqlite3_collation_needed16</a></li>
|
|
<li><a href='#sqlite3_commit_hook'>sqlite3_commit_hook</a></li>
|
|
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation</a></li>
|
|
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation16</a></li>
|
|
<li><a href='#sqlite3_create_collation'>sqlite3_create_collation_v2</a></li>
|
|
<li><a href='#sqlite3_create_function'>sqlite3_create_function</a></li>
|
|
<li><a href='#sqlite3_create_function'>sqlite3_create_function16</a></li>
|
|
<li><a href='#sqlite3_create_function'>sqlite3_create_function_v2</a></li>
|
|
<li><a href='#sqlite3_create_module'>sqlite3_create_module</a></li>
|
|
<li><a href='#sqlite3_create_module'>sqlite3_create_module_v2</a></li>
|
|
<li><a href='#sqlite3_create_function'>sqlite3_create_window_function</a></li>
|
|
<li><a href='#sqlite3_db_config'>sqlite3_db_config</a></li>
|
|
<li><a href='#sqlite3_db_filename'>sqlite3_db_filename</a></li>
|
|
<li><a href='#sqlite3_db_mutex'>sqlite3_db_mutex</a></li>
|
|
<li><a href='#sqlite3_db_readonly'>sqlite3_db_readonly</a></li>
|
|
<li><a href='#sqlite3_db_release_memory'>sqlite3_db_release_memory</a></li>
|
|
<li><a href='#sqlite3_db_status'>sqlite3_db_status</a></li>
|
|
<li><a href='#sqlite3_drop_modules'>sqlite3_drop_modules</a></li>
|
|
<li><a href='#sqlite3_enable_load_extension'>sqlite3_enable_load_extension</a></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_errcode</a></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_errmsg</a></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_errmsg16</a></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_errstr</a></li>
|
|
<li><a href='#sqlite3_exec'>sqlite3_exec</a></li>
|
|
<li><a href='#sqlite3_errcode'>sqlite3_extended_errcode</a></li>
|
|
<li><a href='#sqlite3_extended_result_codes'>sqlite3_extended_result_codes</a></li>
|
|
<li><a href='#sqlite3_file_control'>sqlite3_file_control</a></li>
|
|
<li><a href='#sqlite3_free_table'>sqlite3_free_table</a></li>
|
|
<li><a href='#sqlite3_get_autocommit'>sqlite3_get_autocommit</a></li>
|
|
<li><a href='#sqlite3_free_table'>sqlite3_get_table</a></li>
|
|
<li><a href='#sqlite3_interrupt'>sqlite3_interrupt</a></li>
|
|
<li><a href='#sqlite3_last_insert_rowid'>sqlite3_last_insert_rowid</a></li>
|
|
<li><a href='#sqlite3_limit'>sqlite3_limit</a></li>
|
|
<li><a href='#sqlite3_load_extension'>sqlite3_load_extension</a></li>
|
|
<li><a href='#sqlite3_next_stmt'>sqlite3_next_stmt</a></li>
|
|
<li><a href='#sqlite3_overload_function'>sqlite3_overload_function</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare16</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v2</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v3</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v2</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v3</a></li>
|
|
<li><a href='#sqlite3_profile'>sqlite3_profile</a></li>
|
|
<li><a href='#sqlite3_progress_handler'>sqlite3_progress_handler</a></li>
|
|
<li><a href='#sqlite3_commit_hook'>sqlite3_rollback_hook</a></li>
|
|
<li><a href='#sqlite3_set_authorizer'>sqlite3_set_authorizer</a></li>
|
|
<li><a href='#sqlite3_set_last_insert_rowid'>sqlite3_set_last_insert_rowid</a></li>
|
|
<li><a href='#sqlite3_table_column_metadata'>sqlite3_table_column_metadata</a></li>
|
|
<li><a href='#sqlite3_total_changes'>sqlite3_total_changes</a></li>
|
|
<li><a href='#sqlite3_profile'>sqlite3_trace</a></li>
|
|
<li><a href='#sqlite3_trace_v2'>sqlite3_trace_v2</a></li>
|
|
<li><a href='#sqlite3_unlock_notify'>sqlite3_unlock_notify</a></li>
|
|
<li><a href='#sqlite3_update_hook'>sqlite3_update_hook</a></li>
|
|
<li><a href='#sqlite3_wal_autocheckpoint'>sqlite3_wal_autocheckpoint</a></li>
|
|
<li><a href='#sqlite3_wal_checkpoint'>sqlite3_wal_checkpoint</a></li>
|
|
<li><a href='#sqlite3_wal_checkpoint_v2'>sqlite3_wal_checkpoint_v2</a></li>
|
|
<li><a href='#sqlite3_wal_hook'>sqlite3_wal_hook</a></li>
|
|
</ul>
|
|
</div>
|
|
</p>
|
|
<hr><a name="sqlite3_str"></a>
|
|
<h2>Dynamic String Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_str sqlite3_str;
|
|
</pre></blockquote>
|
|
<p>
|
|
An instance of the sqlite3_str object contains a dynamically-sized
|
|
string under construction.</p>
|
|
|
|
<p>The lifecycle of an sqlite3_str object is as follows:
|
|
<ol>
|
|
<li> The sqlite3_str object is created using <a href="#sqlite3_str_new">sqlite3_str_new()</a>.
|
|
<li> Text is appended to the sqlite3_str object using various
|
|
methods, such as <a href="#sqlite3_str_append">sqlite3_str_appendf()</a>.
|
|
<li> The sqlite3_str object is destroyed and the string it created
|
|
is returned using the <a href="#sqlite3_str_finish">sqlite3_str_finish()</a> interface.
|
|
</ol>
|
|
</p><p>Constructor: <a href="#sqlite3_str_new">sqlite3_str_new()</a></p>
|
|
<p>Destructor: <a href="#sqlite3_str_finish">sqlite3_str_finish()</a></p>
|
|
<div class='columns' style='columns: 17em auto;'>
|
|
<ul style='padding-top:0;'>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_append</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_appendall</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_appendchar</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_appendf</a></li>
|
|
<li><a href='#sqlite3_str_errcode'>sqlite3_str_errcode</a></li>
|
|
<li><a href='#sqlite3_str_errcode'>sqlite3_str_length</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_reset</a></li>
|
|
<li><a href='#sqlite3_str_errcode'>sqlite3_str_value</a></li>
|
|
<li><a href='#sqlite3_str_append'>sqlite3_str_vappendf</a></li>
|
|
</ul>
|
|
</div>
|
|
</p>
|
|
<hr><a name="sqlite3_pcache_methods2"></a>
|
|
<h2>Application Defined Page Cache.</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
|
|
struct sqlite3_pcache_methods2 {
|
|
int iVersion;
|
|
void *pArg;
|
|
int (*xInit)(void*);
|
|
void (*xShutdown)(void*);
|
|
sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
|
|
void (*xCachesize)(sqlite3_pcache*, int nCachesize);
|
|
int (*xPagecount)(sqlite3_pcache*);
|
|
sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
|
|
void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
|
|
void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
|
|
unsigned oldKey, unsigned newKey);
|
|
void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
|
|
void (*xDestroy)(sqlite3_pcache*);
|
|
void (*xShrink)(sqlite3_pcache*);
|
|
};
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigpcache2">SQLITE_CONFIG_PCACHE2</a>, ...) interface can
|
|
register an alternative page cache implementation by passing in an
|
|
instance of the sqlite3_pcache_methods2 structure.
|
|
In many applications, most of the heap memory allocated by
|
|
SQLite is used for the page cache.
|
|
By implementing a
|
|
custom page cache using this API, an application can better control
|
|
the amount of memory consumed by SQLite, the way in which
|
|
that memory is allocated and released, and the policies used to
|
|
determine exactly which parts of a database file are cached and for
|
|
how long.</p>
|
|
|
|
<p>The alternative page cache mechanism is an
|
|
extreme measure that is only needed by the most demanding applications.
|
|
The built-in page cache is recommended for most uses.</p>
|
|
|
|
<p>The contents of the sqlite3_pcache_methods2 structure are copied to an
|
|
internal buffer by SQLite within the call to <a href="#sqlite3_config">sqlite3_config</a>. Hence
|
|
the application may discard the parameter after the call to
|
|
<a href="#sqlite3_config">sqlite3_config()</a> returns.</p>
|
|
|
|
<p><a name="thexinitpagecachemethod"></a>
|
|
|
|
The xInit() method is called once for each effective
|
|
call to <a href="#sqlite3_initialize">sqlite3_initialize()</a>
|
|
(usually only once during the lifetime of the process). The xInit()
|
|
method is passed a copy of the sqlite3_pcache_methods2.pArg value.
|
|
The intent of the xInit() method is to set up global data structures
|
|
required by the custom page cache implementation.
|
|
If the xInit() method is NULL, then the
|
|
built-in default page cache is used instead of the application defined
|
|
page cache.</p>
|
|
|
|
<p><a name="thexshutdownpagecachemethod"></a>
|
|
|
|
The xShutdown() method is called by <a href="#sqlite3_initialize">sqlite3_shutdown()</a>.
|
|
It can be used to clean up
|
|
any outstanding resources before process shutdown, if required.
|
|
The xShutdown() method may be NULL.</p>
|
|
|
|
<p>SQLite automatically serializes calls to the xInit method,
|
|
so the xInit method need not be threadsafe. The
|
|
xShutdown method is only called from <a href="#sqlite3_initialize">sqlite3_shutdown()</a> so it does
|
|
not need to be threadsafe either. All other methods must be threadsafe
|
|
in multithreaded applications.</p>
|
|
|
|
<p>SQLite will never invoke xInit() more than once without an intervening
|
|
call to xShutdown().</p>
|
|
|
|
<p><a name="thexcreatepagecachemethods"></a>
|
|
|
|
SQLite invokes the xCreate() method to construct a new cache instance.
|
|
SQLite will typically create one cache instance for each open database file,
|
|
though this is not guaranteed. The
|
|
first parameter, szPage, is the size in bytes of the pages that must
|
|
be allocated by the cache. szPage will always a power of two. The
|
|
second parameter szExtra is a number of bytes of extra storage
|
|
associated with each page cache entry. The szExtra parameter will
|
|
a number less than 250. SQLite will use the
|
|
extra szExtra bytes on each page to store metadata about the underlying
|
|
database page on disk. The value passed into szExtra depends
|
|
on the SQLite version, the target platform, and how SQLite was compiled.
|
|
The third argument to xCreate(), bPurgeable, is true if the cache being
|
|
created will be used to cache database pages of a file stored on disk, or
|
|
false if it is used for an in-memory database. The cache implementation
|
|
does not have to do anything special based with the value of bPurgeable;
|
|
it is purely advisory. On a cache where bPurgeable is false, SQLite will
|
|
never invoke xUnpin() except to deliberately delete a page.
|
|
In other words, calls to xUnpin() on a cache with bPurgeable set to
|
|
false will always have the "discard" flag set to true.
|
|
Hence, a cache created with bPurgeable false will
|
|
never contain any unpinned pages.</p>
|
|
|
|
<p><a name="thexcachesizepagecachemethod"></a>
|
|
|
|
The xCachesize() method may be called at any time by SQLite to set the
|
|
suggested maximum cache-size (number of pages stored by) the cache
|
|
instance passed as the first argument. This is the value configured using
|
|
the SQLite "<a href="pragma.html#pragma_cache_size">PRAGMA cache_size</a>" command. As with the bPurgeable
|
|
parameter, the implementation is not required to do anything with this
|
|
value; it is advisory only.</p>
|
|
|
|
<p><a name="thexpagecountpagecachemethods"></a>
|
|
|
|
The xPagecount() method must return the number of pages currently
|
|
stored in the cache, both pinned and unpinned.</p>
|
|
|
|
<p><a name="thexfetchpagecachemethods"></a>
|
|
|
|
The xFetch() method locates a page in the cache and returns a pointer to
|
|
an sqlite3_pcache_page object associated with that page, or a NULL pointer.
|
|
The pBuf element of the returned sqlite3_pcache_page object will be a
|
|
pointer to a buffer of szPage bytes used to store the content of a
|
|
single database page. The pExtra element of sqlite3_pcache_page will be
|
|
a pointer to the szExtra bytes of extra storage that SQLite has requested
|
|
for each entry in the page cache.</p>
|
|
|
|
<p>The page to be fetched is determined by the key. The minimum key value
|
|
is 1. After it has been retrieved using xFetch, the page is considered
|
|
to be "pinned".</p>
|
|
|
|
<p>If the requested page is already in the page cache, then the page cache
|
|
implementation must return a pointer to the page buffer with its content
|
|
intact. If the requested page is not already in the cache, then the
|
|
cache implementation should use the value of the createFlag
|
|
parameter to help it determined what action to take:</p>
|
|
|
|
<p><table border=1 width=85% align=center>
|
|
<tr><th> createFlag <th> Behavior when page is not already in cache
|
|
<tr><td> 0 <td> Do not allocate a new page. Return NULL.
|
|
<tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
|
|
Otherwise return NULL.
|
|
<tr><td> 2 <td> Make every effort to allocate a new page. Only return
|
|
NULL if allocating a new page is effectively impossible.
|
|
</table></p>
|
|
|
|
<p>SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite
|
|
will only use a createFlag of 2 after a prior call with a createFlag of 1
|
|
failed. In between the xFetch() calls, SQLite may
|
|
attempt to unpin one or more cache pages by spilling the content of
|
|
pinned pages to disk and synching the operating system disk cache.</p>
|
|
|
|
<p><a name="thexunpinpagecachemethod"></a>
|
|
|
|
xUnpin() is called by SQLite with a pointer to a currently pinned page
|
|
as its second argument. If the third parameter, discard, is non-zero,
|
|
then the page must be evicted from the cache.
|
|
If the discard parameter is
|
|
zero, then the page may be discarded or retained at the discretion of
|
|
page cache implementation. The page cache implementation
|
|
may choose to evict unpinned pages at any time.</p>
|
|
|
|
<p>The cache must not perform any reference counting. A single
|
|
call to xUnpin() unpins the page regardless of the number of prior calls
|
|
to xFetch().</p>
|
|
|
|
<p><a name="thexrekeypagecachemethods"></a>
|
|
|
|
The xRekey() method is used to change the key value associated with the
|
|
page passed as the second argument. If the cache
|
|
previously contains an entry associated with newKey, it must be
|
|
discarded. Any prior cache entry associated with newKey is guaranteed not
|
|
to be pinned.</p>
|
|
|
|
<p>When SQLite calls the xTruncate() method, the cache must discard all
|
|
existing cache entries with page numbers (keys) greater than or equal
|
|
to the value of the iLimit parameter passed to xTruncate(). If any
|
|
of these pages are pinned, they are implicitly unpinned, meaning that
|
|
they can be safely discarded.</p>
|
|
|
|
<p><a name="thexdestroypagecachemethod"></a>
|
|
|
|
The xDestroy() method is used to delete a cache allocated by xCreate().
|
|
All resources associated with the specified cache should be freed. After
|
|
calling the xDestroy() method, SQLite considers the <a href="#sqlite3_pcache">sqlite3_pcache*</a>
|
|
handle invalid, and will not use it with any other sqlite3_pcache_methods2
|
|
functions.</p>
|
|
|
|
<p><a name="thexshrinkpagecachemethod"></a>
|
|
|
|
SQLite invokes the xShrink() method when it wants the page cache to
|
|
free up as much of heap memory as possible. The page cache implementation
|
|
is not obligated to free any memory, but well-behaved implementations should
|
|
do their best.
|
|
</p><hr><a name="sqlite3_stmt"></a>
|
|
<h2>Prepared Statement Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_stmt sqlite3_stmt;
|
|
</pre></blockquote>
|
|
<p>
|
|
An instance of this object represents a single SQL statement that
|
|
has been compiled into binary form and is ready to be evaluated.</p>
|
|
|
|
<p>Think of each SQL statement as a separate computer program. The
|
|
original SQL text is source code. A prepared statement object
|
|
is the compiled object code. All SQL must be converted into a
|
|
prepared statement before it can be run.</p>
|
|
|
|
<p>The life-cycle of a prepared statement object usually goes like this:</p>
|
|
|
|
<p><ol>
|
|
<li> Create the prepared statement object using <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>.
|
|
<li> Bind values to <a href="lang_expr.html#varparam">parameters</a> using the sqlite3_bind_*()
|
|
interfaces.
|
|
<li> Run the SQL by calling <a href="#sqlite3_step">sqlite3_step()</a> one or more times.
|
|
<li> Reset the prepared statement using <a href="#sqlite3_reset">sqlite3_reset()</a> then go back
|
|
to step 2. Do this zero or more times.
|
|
<li> Destroy the object using <a href="#sqlite3_finalize">sqlite3_finalize()</a>.
|
|
</ol>
|
|
</p><div class='columns' style='columns: 17em auto;'>
|
|
<ul style='padding-top:0;'>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare16</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v2</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare16_v3</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v2</a></li>
|
|
<li><a href='#sqlite3_prepare'>sqlite3_prepare_v3</a></li>
|
|
</ul>
|
|
</div>
|
|
</p>
|
|
<p>Destructor: <a href="#sqlite3_finalize">sqlite3_finalize()</a></p>
|
|
<div class='columns' style='columns: 17em auto;'>
|
|
<ul style='padding-top:0;'>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_blob</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_blob64</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_double</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_int</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_int64</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_null</a></li>
|
|
<li><a href='#sqlite3_bind_parameter_count'>sqlite3_bind_parameter_count</a></li>
|
|
<li><a href='#sqlite3_bind_parameter_index'>sqlite3_bind_parameter_index</a></li>
|
|
<li><a href='#sqlite3_bind_parameter_name'>sqlite3_bind_parameter_name</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_pointer</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text16</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_text64</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_value</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_zeroblob</a></li>
|
|
<li><a href='#sqlite3_bind_blob'>sqlite3_bind_zeroblob64</a></li>
|
|
<li><a href='#sqlite3_clear_bindings'>sqlite3_clear_bindings</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_blob</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_bytes</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_bytes16</a></li>
|
|
<li><a href='#sqlite3_column_count'>sqlite3_column_count</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_database_name</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_database_name16</a></li>
|
|
<li><a href='#sqlite3_column_decltype'>sqlite3_column_decltype</a></li>
|
|
<li><a href='#sqlite3_column_decltype'>sqlite3_column_decltype16</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_double</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_int</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_int64</a></li>
|
|
<li><a href='#sqlite3_column_name'>sqlite3_column_name</a></li>
|
|
<li><a href='#sqlite3_column_name'>sqlite3_column_name16</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_origin_name</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_origin_name16</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_table_name</a></li>
|
|
<li><a href='#sqlite3_column_database_name'>sqlite3_column_table_name16</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_text</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_text16</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_type</a></li>
|
|
<li><a href='#sqlite3_column_blob'>sqlite3_column_value</a></li>
|
|
<li><a href='#sqlite3_data_count'>sqlite3_data_count</a></li>
|
|
<li><a href='#sqlite3_db_handle'>sqlite3_db_handle</a></li>
|
|
<li><a href='#sqlite3_expanded_sql'>sqlite3_expanded_sql</a></li>
|
|
<li><a href='#sqlite3_expanded_sql'>sqlite3_normalized_sql</a></li>
|
|
<li><a href='#sqlite3_reset'>sqlite3_reset</a></li>
|
|
<li><a href='#sqlite3_expanded_sql'>sqlite3_sql</a></li>
|
|
<li><a href='#sqlite3_step'>sqlite3_step</a></li>
|
|
<li><a href='#sqlite3_stmt_busy'>sqlite3_stmt_busy</a></li>
|
|
<li><a href='#sqlite3_stmt_isexplain'>sqlite3_stmt_isexplain</a></li>
|
|
<li><a href='#sqlite3_stmt_readonly'>sqlite3_stmt_readonly</a></li>
|
|
<li><a href='#sqlite3_stmt_scanstatus'>sqlite3_stmt_scanstatus</a></li>
|
|
<li><a href='#sqlite3_stmt_scanstatus_reset'>sqlite3_stmt_scanstatus_reset</a></li>
|
|
<li><a href='#sqlite3_stmt_status'>sqlite3_stmt_status</a></li>
|
|
</ul>
|
|
</div>
|
|
</p>
|
|
<hr><a name="sqlite3_value"></a>
|
|
<h2>Dynamically Typed Value Object</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
typedef struct sqlite3_value sqlite3_value;
|
|
</pre></blockquote>
|
|
<p>
|
|
SQLite uses the sqlite3_value object to represent all values
|
|
that can be stored in a database table. SQLite uses dynamic typing
|
|
for the values it stores. Values stored in sqlite3_value objects
|
|
can be integers, floating point values, strings, BLOBs, or NULL.</p>
|
|
|
|
<p>An sqlite3_value object may be either "protected" or "unprotected".
|
|
Some interfaces require a protected sqlite3_value. Other interfaces
|
|
will accept either a protected or an unprotected sqlite3_value.
|
|
Every interface that accepts sqlite3_value arguments specifies
|
|
whether or not it requires a protected sqlite3_value. The
|
|
<a href="#sqlite3_value_dup">sqlite3_value_dup()</a> interface can be used to construct a new
|
|
protected sqlite3_value from an unprotected sqlite3_value.</p>
|
|
|
|
<p>The terms "protected" and "unprotected" refer to whether or not
|
|
a mutex is held. An internal mutex is held for a protected
|
|
sqlite3_value object but no mutex is held for an unprotected
|
|
sqlite3_value object. If SQLite is compiled to be single-threaded
|
|
(with <a href="compile.html#threadsafe">SQLITE_THREADSAFE=0</a> and with <a href="#sqlite3_threadsafe">sqlite3_threadsafe()</a> returning 0)
|
|
or if SQLite is run in one of reduced mutex modes
|
|
<a href="#sqliteconfigsinglethread">SQLITE_CONFIG_SINGLETHREAD</a> or <a href="#sqliteconfigmultithread">SQLITE_CONFIG_MULTITHREAD</a>
|
|
then there is no distinction between protected and unprotected
|
|
sqlite3_value objects and they can be used interchangeably. However,
|
|
for maximum code portability it is recommended that applications
|
|
still make the distinction between protected and unprotected
|
|
sqlite3_value objects even when not strictly required.</p>
|
|
|
|
<p>The sqlite3_value objects that are passed as parameters into the
|
|
implementation of <a href="appfunc.html">application-defined SQL functions</a> are protected.
|
|
The sqlite3_value object returned by
|
|
<a href="#sqlite3_column_blob">sqlite3_column_value()</a> is unprotected.
|
|
Unprotected sqlite3_value objects may only be used as arguments
|
|
to <a href="#sqlite3_result_blob">sqlite3_result_value()</a>, <a href="#sqlite3_bind_blob">sqlite3_bind_value()</a>, and
|
|
<a href="#sqlite3_value_dup">sqlite3_value_dup()</a>.
|
|
The <a href="#sqlite3_value_blob">sqlite3_value_type()</a> family of
|
|
interfaces require protected sqlite3_value objects.
|
|
</p><div class='columns' style='columns: 17em auto;'>
|
|
<ul style='padding-top:0;'>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_blob</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_bytes</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_bytes16</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_double</a></li>
|
|
<li><a href='#sqlite3_value_dup'>sqlite3_value_dup</a></li>
|
|
<li><a href='#sqlite3_value_dup'>sqlite3_value_free</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_frombind</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_int</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_int64</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_nochange</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_numeric_type</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_pointer</a></li>
|
|
<li><a href='#sqlite3_value_subtype'>sqlite3_value_subtype</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_text</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16be</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_text16le</a></li>
|
|
<li><a href='#sqlite3_value_blob'>sqlite3_value_type</a></li>
|
|
</ul>
|
|
</div>
|
|
</p>
|
|
<hr><a name="sqlite3_aggregate_count"></a>
|
|
<h2>Deprecated Functions</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#ifndef SQLITE_OMIT_DEPRECATED
|
|
int sqlite3_aggregate_count(sqlite3_context*);
|
|
int sqlite3_expired(sqlite3_stmt*);
|
|
int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
|
|
int sqlite3_global_recover(void);
|
|
void sqlite3_thread_cleanup(void);
|
|
int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
|
|
void*,sqlite3_int64);
|
|
#endif
|
|
</pre></blockquote>
|
|
<p>
|
|
These functions are <a href="capi3ref.html">deprecated</a>. In order to maintain
|
|
backwards compatibility with older code, these functions continue
|
|
to be supported. However, new applications should avoid
|
|
the use of these functions. To encourage programmers to avoid
|
|
these functions, we will not explain what they do.
|
|
</p><hr><a name="sqlite3_backup_finish"></a>
|
|
<h2>Online Backup API.</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_backup *sqlite3_backup_init(
|
|
sqlite3 *pDest, /* Destination database handle */
|
|
const char *zDestName, /* Destination database name */
|
|
sqlite3 *pSource, /* Source database handle */
|
|
const char *zSourceName /* Source database name */
|
|
);
|
|
int sqlite3_backup_step(sqlite3_backup *p, int nPage);
|
|
int sqlite3_backup_finish(sqlite3_backup *p);
|
|
int sqlite3_backup_remaining(sqlite3_backup *p);
|
|
int sqlite3_backup_pagecount(sqlite3_backup *p);
|
|
</pre></blockquote>
|
|
<p>
|
|
The backup API copies the content of one database into another.
|
|
It is useful either for creating backups of databases or
|
|
for copying in-memory databases to or from persistent files.</p>
|
|
|
|
<p>See Also: <a href="backup.html">Using the SQLite Online Backup API</a></p>
|
|
|
|
<p>SQLite holds a write transaction open on the destination database file
|
|
for the duration of the backup operation.
|
|
The source database is read-locked only while it is being read;
|
|
it is not locked continuously for the entire backup operation.
|
|
Thus, the backup may be performed on a live source database without
|
|
preventing other database connections from
|
|
reading or writing to the source database while the backup is underway.</p>
|
|
|
|
<p>To perform a backup operation:
|
|
<ol>
|
|
<li><b>sqlite3_backup_init()</b> is called once to initialize the
|
|
backup,
|
|
<li><b>sqlite3_backup_step()</b> is called one or more times to transfer
|
|
the data between the two databases, and finally
|
|
<li><b>sqlite3_backup_finish()</b> is called to release all resources
|
|
associated with the backup operation.
|
|
</ol>
|
|
There should be exactly one call to sqlite3_backup_finish() for each
|
|
successful call to sqlite3_backup_init().</p>
|
|
|
|
<p><a name="sqlite3backupinit"></a>
|
|
<b>sqlite3_backup_init()</b></p>
|
|
|
|
<p>The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
|
|
<a href="#sqlite3">database connection</a> associated with the destination database
|
|
and the database name, respectively.
|
|
The database name is "main" for the main database, "temp" for the
|
|
temporary database, or the name specified after the AS keyword in
|
|
an <a href="lang_attach.html">ATTACH</a> statement for an attached database.
|
|
The S and M arguments passed to
|
|
sqlite3_backup_init(D,N,S,M) identify the <a href="#sqlite3">database connection</a>
|
|
and database name of the source database, respectively.
|
|
The source and destination <a href="#sqlite3">database connections</a> (parameters S and D)
|
|
must be different or else sqlite3_backup_init(D,N,S,M) will fail with
|
|
an error.</p>
|
|
|
|
<p>A call to sqlite3_backup_init() will fail, returning NULL, if
|
|
there is already a read or read-write transaction open on the
|
|
destination database.</p>
|
|
|
|
<p>If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
|
|
returned and an error code and error message are stored in the
|
|
destination <a href="#sqlite3">database connection</a> D.
|
|
The error code and message for the failed call to sqlite3_backup_init()
|
|
can be retrieved using the <a href="#sqlite3_errcode">sqlite3_errcode()</a>, <a href="#sqlite3_errcode">sqlite3_errmsg()</a>, and/or
|
|
<a href="#sqlite3_errcode">sqlite3_errmsg16()</a> functions.
|
|
A successful call to sqlite3_backup_init() returns a pointer to an
|
|
<a href="#sqlite3_backup">sqlite3_backup</a> object.
|
|
The <a href="#sqlite3_backup">sqlite3_backup</a> object may be used with the sqlite3_backup_step() and
|
|
sqlite3_backup_finish() functions to perform the specified backup
|
|
operation.</p>
|
|
|
|
<p><a name="sqlite3backupstep"></a>
|
|
<b>sqlite3_backup_step()</b></p>
|
|
|
|
<p>Function sqlite3_backup_step(B,N) will copy up to N pages between
|
|
the source and destination databases specified by <a href="#sqlite3_backup">sqlite3_backup</a> object B.
|
|
If N is negative, all remaining source pages are copied.
|
|
If sqlite3_backup_step(B,N) successfully copies N pages and there
|
|
are still more pages to be copied, then the function returns <a href="#SQLITE_ABORT">SQLITE_OK</a>.
|
|
If sqlite3_backup_step(B,N) successfully finishes copying all pages
|
|
from source to destination, then it returns <a href="#SQLITE_ABORT">SQLITE_DONE</a>.
|
|
If an error occurs while running sqlite3_backup_step(B,N),
|
|
then an <a href="rescode.html">error code</a> is returned. As well as <a href="#SQLITE_ABORT">SQLITE_OK</a> and
|
|
<a href="#SQLITE_ABORT">SQLITE_DONE</a>, a call to sqlite3_backup_step() may return <a href="#SQLITE_ABORT">SQLITE_READONLY</a>,
|
|
<a href="#SQLITE_ABORT">SQLITE_NOMEM</a>, <a href="#SQLITE_ABORT">SQLITE_BUSY</a>, <a href="#SQLITE_ABORT">SQLITE_LOCKED</a>, or an
|
|
<a href="#SQLITE_ABORT_ROLLBACK">SQLITE_IOERR_XXX</a> extended error code.</p>
|
|
|
|
<p>The sqlite3_backup_step() might return <a href="#SQLITE_ABORT">SQLITE_READONLY</a> if
|
|
<ol>
|
|
<li> the destination database was opened read-only, or
|
|
<li> the destination database is using write-ahead-log journaling
|
|
and the destination and source page sizes differ, or
|
|
<li> the destination database is an in-memory database and the
|
|
destination and source page sizes differ.
|
|
</ol></p>
|
|
|
|
<p>If sqlite3_backup_step() cannot obtain a required file-system lock, then
|
|
the <a href="#sqlite3_busy_handler">busy-handler function</a>
|
|
is invoked (if one is specified). If the
|
|
busy-handler returns non-zero before the lock is available, then
|
|
<a href="#SQLITE_ABORT">SQLITE_BUSY</a> is returned to the caller. In this case the call to
|
|
sqlite3_backup_step() can be retried later. If the source
|
|
<a href="#sqlite3">database connection</a>
|
|
is being used to write to the source database when sqlite3_backup_step()
|
|
is called, then <a href="#SQLITE_ABORT">SQLITE_LOCKED</a> is returned immediately. Again, in this
|
|
case the call to sqlite3_backup_step() can be retried later on. If
|
|
<a href="#SQLITE_ABORT_ROLLBACK">SQLITE_IOERR_XXX</a>, <a href="#SQLITE_ABORT">SQLITE_NOMEM</a>, or
|
|
<a href="#SQLITE_ABORT">SQLITE_READONLY</a> is returned, then
|
|
there is no point in retrying the call to sqlite3_backup_step(). These
|
|
errors are considered fatal. The application must accept
|
|
that the backup operation has failed and pass the backup operation handle
|
|
to the sqlite3_backup_finish() to release associated resources.</p>
|
|
|
|
<p>The first call to sqlite3_backup_step() obtains an exclusive lock
|
|
on the destination file. The exclusive lock is not released until either
|
|
sqlite3_backup_finish() is called or the backup operation is complete
|
|
and sqlite3_backup_step() returns <a href="#SQLITE_ABORT">SQLITE_DONE</a>. Every call to
|
|
sqlite3_backup_step() obtains a <a href="lockingv3.html#shared_lock">shared lock</a> on the source database that
|
|
lasts for the duration of the sqlite3_backup_step() call.
|
|
Because the source database is not locked between calls to
|
|
sqlite3_backup_step(), the source database may be modified mid-way
|
|
through the backup process. If the source database is modified by an
|
|
external process or via a database connection other than the one being
|
|
used by the backup operation, then the backup will be automatically
|
|
restarted by the next call to sqlite3_backup_step(). If the source
|
|
database is modified by the using the same database connection as is used
|
|
by the backup operation, then the backup database is automatically
|
|
updated at the same time.</p>
|
|
|
|
<p><a name="sqlite3backupfinish"></a>
|
|
<b>sqlite3_backup_finish()</b></p>
|
|
|
|
<p>When sqlite3_backup_step() has returned <a href="#SQLITE_ABORT">SQLITE_DONE</a>, or when the
|
|
application wishes to abandon the backup operation, the application
|
|
should destroy the <a href="#sqlite3_backup">sqlite3_backup</a> by passing it to sqlite3_backup_finish().
|
|
The sqlite3_backup_finish() interfaces releases all
|
|
resources associated with the <a href="#sqlite3_backup">sqlite3_backup</a> object.
|
|
If sqlite3_backup_step() has not yet returned <a href="#SQLITE_ABORT">SQLITE_DONE</a>, then any
|
|
active write-transaction on the destination database is rolled back.
|
|
The <a href="#sqlite3_backup">sqlite3_backup</a> object is invalid
|
|
and may not be used following a call to sqlite3_backup_finish().</p>
|
|
|
|
<p>The value returned by sqlite3_backup_finish is <a href="#SQLITE_ABORT">SQLITE_OK</a> if no
|
|
sqlite3_backup_step() errors occurred, regardless or whether or not
|
|
sqlite3_backup_step() completed.
|
|
If an out-of-memory condition or IO error occurred during any prior
|
|
sqlite3_backup_step() call on the same <a href="#sqlite3_backup">sqlite3_backup</a> object, then
|
|
sqlite3_backup_finish() returns the corresponding <a href="rescode.html">error code</a>.</p>
|
|
|
|
<p>A return of <a href="#SQLITE_ABORT">SQLITE_BUSY</a> or <a href="#SQLITE_ABORT">SQLITE_LOCKED</a> from sqlite3_backup_step()
|
|
is not a permanent error and does not affect the return value of
|
|
sqlite3_backup_finish().</p>
|
|
|
|
<p><a name="sqlite3backupremaining"></a>
|
|
<a name="sqlite3backuppagecount"></a>
|
|
|
|
<b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b></p>
|
|
|
|
<p>The sqlite3_backup_remaining() routine returns the number of pages still
|
|
to be backed up at the conclusion of the most recent sqlite3_backup_step().
|
|
The sqlite3_backup_pagecount() routine returns the total number of pages
|
|
in the source database at the conclusion of the most recent
|
|
sqlite3_backup_step().
|
|
The values returned by these functions are only updated by
|
|
sqlite3_backup_step(). If the source database is modified in a way that
|
|
changes the size of the source database or the number of pages remaining,
|
|
those changes are not reflected in the output of sqlite3_backup_pagecount()
|
|
and sqlite3_backup_remaining() until after the next
|
|
sqlite3_backup_step().</p>
|
|
|
|
<p><b>Concurrent Usage of Database Handles</b></p>
|
|
|
|
<p>The source <a href="#sqlite3">database connection</a> may be used by the application for other
|
|
purposes while a backup operation is underway or being initialized.
|
|
If SQLite is compiled and configured to support threadsafe database
|
|
connections, then the source database connection may be used concurrently
|
|
from within other threads.</p>
|
|
|
|
<p>However, the application must guarantee that the destination
|
|
<a href="#sqlite3">database connection</a> is not passed to any other API (by any thread) after
|
|
sqlite3_backup_init() is called and before the corresponding call to
|
|
sqlite3_backup_finish(). SQLite does not currently check to see
|
|
if the application incorrectly accesses the destination <a href="#sqlite3">database connection</a>
|
|
and so no error code is reported, but the operations may malfunction
|
|
nevertheless. Use of the destination database connection while a
|
|
backup is in progress might also also cause a mutex deadlock.</p>
|
|
|
|
<p>If running in <a href="sharedcache.html">shared cache mode</a>, the application must
|
|
guarantee that the shared cache used by the destination database
|
|
is not accessed while the backup is running. In practice this means
|
|
that the application must guarantee that the disk file being
|
|
backed up to is not accessed by any connection within the process,
|
|
not just the specific connection that was passed to sqlite3_backup_init().</p>
|
|
|
|
<p>The <a href="#sqlite3_backup">sqlite3_backup</a> object itself is partially threadsafe. Multiple
|
|
threads may safely make multiple concurrent calls to sqlite3_backup_step().
|
|
However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
|
|
APIs are not strictly speaking threadsafe. If they are invoked at the
|
|
same time as another thread is invoking sqlite3_backup_step() it is
|
|
possible that they return invalid values.
|
|
</p><hr><a name="sqlite3_close"></a>
|
|
<h2>Closing A Database Connection</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_close(sqlite3*);
|
|
int sqlite3_close_v2(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_close() and sqlite3_close_v2() routines are destructors
|
|
for the <a href="#sqlite3">sqlite3</a> object.
|
|
Calls to sqlite3_close() and sqlite3_close_v2() return <a href="#SQLITE_ABORT">SQLITE_OK</a> if
|
|
the <a href="#sqlite3">sqlite3</a> object is successfully destroyed and all associated
|
|
resources are deallocated.</p>
|
|
|
|
<p>Ideally, applications should <a href="#sqlite3_finalize">finalize</a> all
|
|
<a href="#sqlite3_stmt">prepared statements</a>, <a href="#sqlite3_blob_close">close</a> all <a href="#sqlite3_blob">BLOB handles</a>, and
|
|
<a href="#sqlite3backupfinish">finish</a> all <a href="#sqlite3_backup">sqlite3_backup</a> objects associated
|
|
with the <a href="#sqlite3">sqlite3</a> object prior to attempting to close the object.
|
|
If the database connection is associated with unfinalized prepared
|
|
statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
|
|
sqlite3_close() will leave the database connection open and return
|
|
<a href="#SQLITE_ABORT">SQLITE_BUSY</a>. If sqlite3_close_v2() is called with unfinalized prepared
|
|
statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
|
|
it returns <a href="#SQLITE_ABORT">SQLITE_OK</a> regardless, but instead of deallocating the database
|
|
connection immediately, it marks the database connection as an unusable
|
|
"zombie" and makes arrangements to automatically deallocate the database
|
|
connection after all prepared statements are finalized, all BLOB handles
|
|
are closed, and all backups have finished. The sqlite3_close_v2() interface
|
|
is intended for use with host languages that are garbage collected, and
|
|
where the order in which destructors are called is arbitrary.</p>
|
|
|
|
<p>If an <a href="#sqlite3">sqlite3</a> object is destroyed while a transaction is open,
|
|
the transaction is automatically rolled back.</p>
|
|
|
|
<p>The C parameter to <a href="#sqlite3_close">sqlite3_close(C)</a> and <a href="#sqlite3_close">sqlite3_close_v2(C)</a>
|
|
must be either a NULL
|
|
pointer or an <a href="#sqlite3">sqlite3</a> object pointer obtained
|
|
from <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open16()</a>, or
|
|
<a href="#sqlite3_open">sqlite3_open_v2()</a>, and not previously closed.
|
|
Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
|
|
argument is a harmless no-op.
|
|
</p><hr><a name="sqlite3_collation_needed"></a>
|
|
<h2>Collation Needed Callbacks</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_collation_needed(
|
|
sqlite3*,
|
|
void*,
|
|
void(*)(void*,sqlite3*,int eTextRep,const char*)
|
|
);
|
|
int sqlite3_collation_needed16(
|
|
sqlite3*,
|
|
void*,
|
|
void(*)(void*,sqlite3*,int eTextRep,const void*)
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
To avoid having to register all collation sequences before a database
|
|
can be used, a single callback function may be registered with the
|
|
<a href="#sqlite3">database connection</a> to be invoked whenever an undefined collation
|
|
sequence is required.</p>
|
|
|
|
<p>If the function is registered using the sqlite3_collation_needed() API,
|
|
then it is passed the names of undefined collation sequences as strings
|
|
encoded in UTF-8. If sqlite3_collation_needed16() is used,
|
|
the names are passed as UTF-16 in machine native byte order.
|
|
A call to either function replaces the existing collation-needed callback.</p>
|
|
|
|
<p>When the callback is invoked, the first argument passed is a copy
|
|
of the second argument to sqlite3_collation_needed() or
|
|
sqlite3_collation_needed16(). The second argument is the database
|
|
connection. The third argument is one of <a href="#SQLITE_ANY">SQLITE_UTF8</a>, <a href="#SQLITE_ANY">SQLITE_UTF16BE</a>,
|
|
or <a href="#SQLITE_ANY">SQLITE_UTF16LE</a>, indicating the most desirable form of the collation
|
|
sequence function required. The fourth parameter is the name of the
|
|
required collation sequence.</p>
|
|
|
|
<p>The callback function should register the desired collation using
|
|
<a href="#sqlite3_create_collation">sqlite3_create_collation()</a>, <a href="#sqlite3_create_collation">sqlite3_create_collation16()</a>, or
|
|
<a href="#sqlite3_create_collation">sqlite3_create_collation_v2()</a>.
|
|
</p><hr><a name="sqlite3_column_database_name"></a>
|
|
<h2>Source Of Data In A Query Result</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const char *sqlite3_column_database_name(sqlite3_stmt*,int);
|
|
const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
|
|
const char *sqlite3_column_table_name(sqlite3_stmt*,int);
|
|
const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
|
|
const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
|
|
const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines provide a means to determine the database, table, and
|
|
table column that is the origin of a particular result column in
|
|
<a href="lang_select.html">SELECT</a> statement.
|
|
The name of the database or table or column can be returned as
|
|
either a UTF-8 or UTF-16 string. The _database_ routines return
|
|
the database name, the _table_ routines return the table name, and
|
|
the origin_ routines return the column name.
|
|
The returned string is valid until the <a href="#sqlite3_stmt">prepared statement</a> is destroyed
|
|
using <a href="#sqlite3_finalize">sqlite3_finalize()</a> or until the statement is automatically
|
|
reprepared by the first call to <a href="#sqlite3_step">sqlite3_step()</a> for a particular run
|
|
or until the same information is requested
|
|
again in a different encoding.</p>
|
|
|
|
<p>The names returned are the original un-aliased names of the
|
|
database, table, and column.</p>
|
|
|
|
<p>The first argument to these interfaces is a <a href="#sqlite3_stmt">prepared statement</a>.
|
|
These functions return information about the Nth result column returned by
|
|
the statement, where N is the second function argument.
|
|
The left-most column is column 0 for these routines.</p>
|
|
|
|
<p>If the Nth column returned by the statement is an expression or
|
|
subquery and is not a column value, then all of these functions return
|
|
NULL. These routines might also return NULL if a memory allocation error
|
|
occurs. Otherwise, they return the name of the attached database, table,
|
|
or column that query result column was extracted from.</p>
|
|
|
|
<p>As with all other SQLite APIs, those whose names end with "16" return
|
|
UTF-16 encoded strings and the other functions return UTF-8.</p>
|
|
|
|
<p>These APIs are only available if the library was compiled with the
|
|
<a href="compile.html#enable_column_metadata">SQLITE_ENABLE_COLUMN_METADATA</a> C-preprocessor symbol.</p>
|
|
|
|
<p>If two or more threads call one or more
|
|
<a href="#sqlite3_column_database_name">column metadata interfaces</a>
|
|
for the same <a href="#sqlite3_stmt">prepared statement</a> and result column
|
|
at the same time then the results are undefined.
|
|
</p><hr><a name="sqlite3_column_decltype"></a>
|
|
<h2>Declared Datatype Of A Query Result</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const char *sqlite3_column_decltype(sqlite3_stmt*,int);
|
|
const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
|
|
</pre></blockquote>
|
|
<p>
|
|
The first parameter is a <a href="#sqlite3_stmt">prepared statement</a>.
|
|
If this statement is a <a href="lang_select.html">SELECT</a> statement and the Nth column of the
|
|
returned result set of that <a href="lang_select.html">SELECT</a> is a table column (not an
|
|
expression or subquery) then the declared type of the table
|
|
column is returned. If the Nth column of the result set is an
|
|
expression or subquery, then a NULL pointer is returned.
|
|
The returned string is always UTF-8 encoded.</p>
|
|
|
|
<p>For example, given the database schema:</p>
|
|
|
|
<p>CREATE TABLE t1(c1 VARIANT);</p>
|
|
|
|
<p>and the following statement to be compiled:</p>
|
|
|
|
<p>SELECT c1 + 1, c1 FROM t1;</p>
|
|
|
|
<p>this routine would return the string "VARIANT" for the second result
|
|
column (i==1), and a NULL pointer for the first result column (i==0).</p>
|
|
|
|
<p>SQLite uses dynamic run-time typing. So just because a column
|
|
is declared to contain a particular type does not mean that the
|
|
data stored in that column is of the declared type. SQLite is
|
|
strongly typed, but the typing is dynamic not static. Type
|
|
is associated with individual values, not with the containers
|
|
used to hold those values.
|
|
</p><hr><a name="sqlite3_column_name"></a>
|
|
<h2>Column Names In A Result Set</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const char *sqlite3_column_name(sqlite3_stmt*, int N);
|
|
const void *sqlite3_column_name16(sqlite3_stmt*, int N);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines return the name assigned to a particular column
|
|
in the result set of a <a href="lang_select.html">SELECT</a> statement. The sqlite3_column_name()
|
|
interface returns a pointer to a zero-terminated UTF-8 string
|
|
and sqlite3_column_name16() returns a pointer to a zero-terminated
|
|
UTF-16 string. The first parameter is the <a href="#sqlite3_stmt">prepared statement</a>
|
|
that implements the <a href="lang_select.html">SELECT</a> statement. The second parameter is the
|
|
column number. The leftmost column is number 0.</p>
|
|
|
|
<p>The returned string pointer is valid until either the <a href="#sqlite3_stmt">prepared statement</a>
|
|
is destroyed by <a href="#sqlite3_finalize">sqlite3_finalize()</a> or until the statement is automatically
|
|
reprepared by the first call to <a href="#sqlite3_step">sqlite3_step()</a> for a particular run
|
|
or until the next call to
|
|
sqlite3_column_name() or sqlite3_column_name16() on the same column.</p>
|
|
|
|
<p>If sqlite3_malloc() fails during the processing of either routine
|
|
(for example during a conversion from UTF-8 to UTF-16) then a
|
|
NULL pointer is returned.</p>
|
|
|
|
<p>The name of a result column is the value of the "AS" clause for
|
|
that column, if there is an AS clause. If there is no AS clause
|
|
then the name of the column is unspecified and may change from
|
|
one release of SQLite to the next.
|
|
</p><hr><a name="sqlite3_commit_hook"></a>
|
|
<h2>Commit And Rollback Notification Callbacks</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
|
|
void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_commit_hook() interface registers a callback
|
|
function to be invoked whenever a transaction is <a href="lang_transaction.html">committed</a>.
|
|
Any callback set by a previous call to sqlite3_commit_hook()
|
|
for the same database connection is overridden.
|
|
The sqlite3_rollback_hook() interface registers a callback
|
|
function to be invoked whenever a transaction is <a href="lang_transaction.html">rolled back</a>.
|
|
Any callback set by a previous call to sqlite3_rollback_hook()
|
|
for the same database connection is overridden.
|
|
The pArg argument is passed through to the callback.
|
|
If the callback on a commit hook function returns non-zero,
|
|
then the commit is converted into a rollback.</p>
|
|
|
|
<p>The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
|
|
return the P argument from the previous call of the same function
|
|
on the same <a href="#sqlite3">database connection</a> D, or NULL for
|
|
the first call for each function on D.</p>
|
|
|
|
<p>The commit and rollback hook callbacks are not reentrant.
|
|
The callback implementation must not do anything that will modify
|
|
the database connection that invoked the callback. Any actions
|
|
to modify the database connection must be deferred until after the
|
|
completion of the <a href="#sqlite3_step">sqlite3_step()</a> call that triggered the commit
|
|
or rollback hook in the first place.
|
|
Note that running any other SQL statements, including SELECT statements,
|
|
or merely calling <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and <a href="#sqlite3_step">sqlite3_step()</a> will modify
|
|
the database connections for the meaning of "modify" in this paragraph.</p>
|
|
|
|
<p>Registering a NULL function disables the callback.</p>
|
|
|
|
<p>When the commit hook callback routine returns zero, the <a href="lang_transaction.html">COMMIT</a>
|
|
operation is allowed to continue normally. If the commit hook
|
|
returns non-zero, then the <a href="lang_transaction.html">COMMIT</a> is converted into a <a href="lang_transaction.html">ROLLBACK</a>.
|
|
The rollback hook is invoked on a rollback that results from a commit
|
|
hook returning non-zero, just as it would be with any other rollback.</p>
|
|
|
|
<p>For the purposes of this API, a transaction is said to have been
|
|
rolled back if an explicit "ROLLBACK" statement is executed, or
|
|
an error or constraint causes an implicit rollback to occur.
|
|
The rollback callback is not invoked if a transaction is
|
|
automatically rolled back because the database connection is closed.</p>
|
|
|
|
<p>See also the <a href="#sqlite3_update_hook">sqlite3_update_hook()</a> interface.
|
|
</p><hr><a name="sqlite3_compileoption_get"></a>
|
|
<h2>Run-Time Library Compilation Options Diagnostics</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
|
|
int sqlite3_compileoption_used(const char *zOptName);
|
|
const char *sqlite3_compileoption_get(int N);
|
|
#else
|
|
# define sqlite3_compileoption_used(X) 0
|
|
# define sqlite3_compileoption_get(X) ((void*)0)
|
|
#endif
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_compileoption_used() function returns 0 or 1
|
|
indicating whether the specified option was defined at
|
|
compile time. The SQLITE_ prefix may be omitted from the
|
|
option name passed to sqlite3_compileoption_used().</p>
|
|
|
|
<p>The sqlite3_compileoption_get() function allows iterating
|
|
over the list of options that were defined at compile time by
|
|
returning the N-th compile time option string. If N is out of range,
|
|
sqlite3_compileoption_get() returns a NULL pointer. The SQLITE_
|
|
prefix is omitted from any strings returned by
|
|
sqlite3_compileoption_get().</p>
|
|
|
|
<p>Support for the diagnostic functions sqlite3_compileoption_used()
|
|
and sqlite3_compileoption_get() may be omitted by specifying the
|
|
<a href="compile.html#omit_compileoption_diags">SQLITE_OMIT_COMPILEOPTION_DIAGS</a> option at compile time.</p>
|
|
|
|
<p>See also: SQL functions <a href="lang_corefunc.html#sqlite_compileoption_used">sqlite_compileoption_used()</a> and
|
|
<a href="lang_corefunc.html#sqlite_compileoption_get">sqlite_compileoption_get()</a> and the <a href="pragma.html#pragma_compile_options">compile_options pragma</a>.
|
|
</p><hr><a name="sqlite3_complete"></a>
|
|
<h2>Determine If An SQL Statement Is Complete</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_complete(const char *sql);
|
|
int sqlite3_complete16(const void *sql);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines are useful during command-line input to determine if the
|
|
currently entered text seems to form a complete SQL statement or
|
|
if additional input is needed before sending the text into
|
|
SQLite for parsing. These routines return 1 if the input string
|
|
appears to be a complete SQL statement. A statement is judged to be
|
|
complete if it ends with a semicolon token and is not a prefix of a
|
|
well-formed CREATE TRIGGER statement. Semicolons that are embedded within
|
|
string literals or quoted identifier names or comments are not
|
|
independent tokens (they are part of the token in which they are
|
|
embedded) and thus do not count as a statement terminator. Whitespace
|
|
and comments that follow the final semicolon are ignored.</p>
|
|
|
|
<p>These routines return 0 if the statement is incomplete. If a
|
|
memory allocation fails, then SQLITE_NOMEM is returned.</p>
|
|
|
|
<p>These routines do not parse the SQL statements thus
|
|
will not detect syntactically incorrect SQL.</p>
|
|
|
|
<p>If SQLite has not been initialized using <a href="#sqlite3_initialize">sqlite3_initialize()</a> prior
|
|
to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
|
|
automatically by sqlite3_complete16(). If that initialization fails,
|
|
then the return value from sqlite3_complete16() will be non-zero
|
|
regardless of whether or not the input SQL is complete.</p>
|
|
|
|
<p>The input to <a href="#sqlite3_complete">sqlite3_complete()</a> must be a zero-terminated
|
|
UTF-8 string.</p>
|
|
|
|
<p>The input to <a href="#sqlite3_complete">sqlite3_complete16()</a> must be a zero-terminated
|
|
UTF-16 string in native byte order.
|
|
</p><hr><a name="sqlite3_create_collation"></a>
|
|
<h2>Define New Collating Sequences</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_create_collation(
|
|
sqlite3*,
|
|
const char *zName,
|
|
int eTextRep,
|
|
void *pArg,
|
|
int(*xCompare)(void*,int,const void*,int,const void*)
|
|
);
|
|
int sqlite3_create_collation_v2(
|
|
sqlite3*,
|
|
const char *zName,
|
|
int eTextRep,
|
|
void *pArg,
|
|
int(*xCompare)(void*,int,const void*,int,const void*),
|
|
void(*xDestroy)(void*)
|
|
);
|
|
int sqlite3_create_collation16(
|
|
sqlite3*,
|
|
const void *zName,
|
|
int eTextRep,
|
|
void *pArg,
|
|
int(*xCompare)(void*,int,const void*,int,const void*)
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
These functions add, remove, or modify a <a href="datatype3.html#collation">collation</a> associated
|
|
with the <a href="#sqlite3">database connection</a> specified as the first argument.</p>
|
|
|
|
<p>The name of the collation is a UTF-8 string
|
|
for sqlite3_create_collation() and sqlite3_create_collation_v2()
|
|
and a UTF-16 string in native byte order for sqlite3_create_collation16().
|
|
Collation names that compare equal according to <a href="#sqlite3_stricmp">sqlite3_strnicmp()</a> are
|
|
considered to be the same name.</p>
|
|
|
|
<p>The third argument (eTextRep) must be one of the constants:
|
|
<ul>
|
|
<li> <a href="#SQLITE_ANY">SQLITE_UTF8</a>,
|
|
<li> <a href="#SQLITE_ANY">SQLITE_UTF16LE</a>,
|
|
<li> <a href="#SQLITE_ANY">SQLITE_UTF16BE</a>,
|
|
<li> <a href="#SQLITE_ANY">SQLITE_UTF16</a>, or
|
|
<li> <a href="#SQLITE_ANY">SQLITE_UTF16_ALIGNED</a>.
|
|
</ul>
|
|
The eTextRep argument determines the encoding of strings passed
|
|
to the collating function callback, xCompare.
|
|
The <a href="#SQLITE_ANY">SQLITE_UTF16</a> and <a href="#SQLITE_ANY">SQLITE_UTF16_ALIGNED</a> values for eTextRep
|
|
force strings to be UTF16 with native byte order.
|
|
The <a href="#SQLITE_ANY">SQLITE_UTF16_ALIGNED</a> value for eTextRep forces strings to begin
|
|
on an even byte address.</p>
|
|
|
|
<p>The fourth argument, pArg, is an application data pointer that is passed
|
|
through as the first argument to the collating function callback.</p>
|
|
|
|
<p>The fifth argument, xCompare, is a pointer to the collating function.
|
|
Multiple collating functions can be registered using the same name but
|
|
with different eTextRep parameters and SQLite will use whichever
|
|
function requires the least amount of data transformation.
|
|
If the xCompare argument is NULL then the collating function is
|
|
deleted. When all collating functions having the same name are deleted,
|
|
that collation is no longer usable.</p>
|
|
|
|
<p>The collating function callback is invoked with a copy of the pArg
|
|
application data pointer and with two strings in the encoding specified
|
|
by the eTextRep argument. The two integer parameters to the collating
|
|
function callback are the length of the two strings, in bytes. The collating
|
|
function must return an integer that is negative, zero, or positive
|
|
if the first string is less than, equal to, or greater than the second,
|
|
respectively. A collating function must always return the same answer
|
|
given the same inputs. If two or more collating functions are registered
|
|
to the same collation name (using different eTextRep values) then all
|
|
must give an equivalent answer when invoked with equivalent strings.
|
|
The collating function must obey the following properties for all
|
|
strings A, B, and C:</p>
|
|
|
|
<p><ol>
|
|
<li> If A==B then B==A.
|
|
<li> If A==B and B==C then A==C.
|
|
<li> If A<B THEN B>A.
|
|
<li> If A<B and B<C then A<C.
|
|
</ol></p>
|
|
|
|
<p>If a collating function fails any of the above constraints and that
|
|
collating function is registered and used, then the behavior of SQLite
|
|
is undefined.</p>
|
|
|
|
<p>The sqlite3_create_collation_v2() works like sqlite3_create_collation()
|
|
with the addition that the xDestroy callback is invoked on pArg when
|
|
the collating function is deleted.
|
|
Collating functions are deleted when they are overridden by later
|
|
calls to the collation creation functions or when the
|
|
<a href="#sqlite3">database connection</a> is closed using <a href="#sqlite3_close">sqlite3_close()</a>.</p>
|
|
|
|
<p>The xDestroy callback is <u>not</u> called if the
|
|
sqlite3_create_collation_v2() function fails. Applications that invoke
|
|
sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
|
|
check the return code and dispose of the application data pointer
|
|
themselves rather than expecting SQLite to deal with it for them.
|
|
This is different from every other SQLite interface. The inconsistency
|
|
is unfortunate but cannot be changed without breaking backwards
|
|
compatibility.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_collation_needed">sqlite3_collation_needed()</a> and <a href="#sqlite3_collation_needed">sqlite3_collation_needed16()</a>.
|
|
</p><hr><a name="sqlite3_create_filename"></a>
|
|
<h2>Create and Destroy VFS Filenames</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
char *sqlite3_create_filename(
|
|
const char *zDatabase,
|
|
const char *zJournal,
|
|
const char *zWal,
|
|
int nParam,
|
|
const char **azParam
|
|
);
|
|
void sqlite3_free_filename(char*);
|
|
</pre></blockquote>
|
|
<p>
|
|
These interfces are provided for use by <a href="vfs.html#shim">VFS shim</a> implementations and
|
|
are not useful outside of that context.</p>
|
|
|
|
<p>The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
|
|
database filename D with corresponding journal file J and WAL file W and
|
|
with N URI parameters key/values pairs in the array P. The result from
|
|
sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
|
|
is safe to pass to routines like:
|
|
<ul>
|
|
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_parameter()</a>,
|
|
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_boolean()</a>,
|
|
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_int64()</a>,
|
|
<li> <a href="#sqlite3_uri_boolean">sqlite3_uri_key()</a>,
|
|
<li> <a href="#sqlite3_filename_database">sqlite3_filename_database()</a>,
|
|
<li> <a href="#sqlite3_filename_database">sqlite3_filename_journal()</a>, or
|
|
<li> <a href="#sqlite3_filename_database">sqlite3_filename_wal()</a>.
|
|
</ul>
|
|
If a memory allocation error occurs, sqlite3_create_filename() might
|
|
return a NULL pointer. The memory obtained from sqlite3_create_filename(X)
|
|
must be released by a corresponding call to sqlite3_free_filename(Y).</p>
|
|
|
|
<p>The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
|
|
of 2*N pointers to strings. Each pair of pointers in this array corresponds
|
|
to a key and value for a query parameter. The P parameter may be a NULL
|
|
pointer if N is zero. None of the 2*N pointers in the P array may be
|
|
NULL pointers and key pointers should not be empty strings.
|
|
None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
|
|
be NULL pointers, though they can be empty strings.</p>
|
|
|
|
<p>The sqlite3_free_filename(Y) routine releases a memory allocation
|
|
previously obtained from sqlite3_create_filename(). Invoking
|
|
sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.</p>
|
|
|
|
<p>If the Y parameter to sqlite3_free_filename(Y) is anything other
|
|
than a NULL pointer or a pointer previously acquired from
|
|
sqlite3_create_filename(), then bad things such as heap
|
|
corruption or segfaults may occur. The value Y should be
|
|
used again after sqlite3_free_filename(Y) has been called. This means
|
|
that if the <a href="#sqlite3vfsxopen">sqlite3_vfs.xOpen()</a> method of a VFS has been called using Y,
|
|
then the corresponding [sqlite3_module.xClose() method should also be
|
|
invoked prior to calling sqlite3_free_filename(Y).
|
|
</p><hr><a name="sqlite3_create_module"></a>
|
|
<h2>Register A Virtual Table Implementation</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_create_module(
|
|
sqlite3 *db, /* SQLite connection to register module with */
|
|
const char *zName, /* Name of the module */
|
|
const sqlite3_module *p, /* Methods for the module */
|
|
void *pClientData /* Client data for xCreate/xConnect */
|
|
);
|
|
int sqlite3_create_module_v2(
|
|
sqlite3 *db, /* SQLite connection to register module with */
|
|
const char *zName, /* Name of the module */
|
|
const sqlite3_module *p, /* Methods for the module */
|
|
void *pClientData, /* Client data for xCreate/xConnect */
|
|
void(*xDestroy)(void*) /* Module destructor function */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines are used to register a new <a href="#sqlite3_module">virtual table module</a> name.
|
|
Module names must be registered before
|
|
creating a new <a href="vtab.html">virtual table</a> using the module and before using a
|
|
preexisting <a href="vtab.html">virtual table</a> for the module.</p>
|
|
|
|
<p>The module name is registered on the <a href="#sqlite3">database connection</a> specified
|
|
by the first parameter. The name of the module is given by the
|
|
second parameter. The third parameter is a pointer to
|
|
the implementation of the <a href="#sqlite3_module">virtual table module</a>. The fourth
|
|
parameter is an arbitrary client data pointer that is passed through
|
|
into the <a href="vtab.html#xcreate">xCreate</a> and <a href="vtab.html#xconnect">xConnect</a> methods of the virtual table module
|
|
when a new virtual table is be being created or reinitialized.</p>
|
|
|
|
<p>The sqlite3_create_module_v2() interface has a fifth parameter which
|
|
is a pointer to a destructor for the pClientData. SQLite will
|
|
invoke the destructor function (if it is not NULL) when SQLite
|
|
no longer needs the pClientData pointer. The destructor will also
|
|
be invoked if the call to sqlite3_create_module_v2() fails.
|
|
The sqlite3_create_module()
|
|
interface is equivalent to sqlite3_create_module_v2() with a NULL
|
|
destructor.</p>
|
|
|
|
<p>If the third parameter (the pointer to the sqlite3_module object) is
|
|
NULL then no new module is create and any existing modules with the
|
|
same name are dropped.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_drop_modules">sqlite3_drop_modules()</a>
|
|
</p><hr><a name="sqlite3_errcode"></a>
|
|
<h2>Error Codes And Messages</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_errcode(sqlite3 *db);
|
|
int sqlite3_extended_errcode(sqlite3 *db);
|
|
const char *sqlite3_errmsg(sqlite3*);
|
|
const void *sqlite3_errmsg16(sqlite3*);
|
|
const char *sqlite3_errstr(int);
|
|
</pre></blockquote>
|
|
<p>
|
|
If the most recent sqlite3_* API call associated with
|
|
<a href="#sqlite3">database connection</a> D failed, then the sqlite3_errcode(D) interface
|
|
returns the numeric <a href="rescode.html">result code</a> or <a href="rescode.html#extrc">extended result code</a> for that
|
|
API call.
|
|
The sqlite3_extended_errcode()
|
|
interface is the same except that it always returns the
|
|
<a href="rescode.html#extrc">extended result code</a> even when extended result codes are
|
|
disabled.</p>
|
|
|
|
<p>The values returned by sqlite3_errcode() and/or
|
|
sqlite3_extended_errcode() might change with each API call.
|
|
Except, there are some interfaces that are guaranteed to never
|
|
change the value of the error code. The error-code preserving
|
|
interfaces are:</p>
|
|
|
|
<p><ul>
|
|
<li> sqlite3_errcode()
|
|
<li> sqlite3_extended_errcode()
|
|
<li> sqlite3_errmsg()
|
|
<li> sqlite3_errmsg16()
|
|
</ul></p>
|
|
|
|
<p>The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
|
|
text that describes the error, as either UTF-8 or UTF-16 respectively.
|
|
Memory to hold the error message string is managed internally.
|
|
The application does not need to worry about freeing the result.
|
|
However, the error string might be overwritten or deallocated by
|
|
subsequent calls to other SQLite interface functions.</p>
|
|
|
|
<p>The sqlite3_errstr() interface returns the English-language text
|
|
that describes the <a href="rescode.html">result code</a>, as UTF-8.
|
|
Memory to hold the error message string is managed internally
|
|
and must not be freed by the application.</p>
|
|
|
|
<p>When the serialized <a href="threadsafe.html">threading mode</a> is in use, it might be the
|
|
case that a second error occurs on a separate thread in between
|
|
the time of the first error and the call to these interfaces.
|
|
When that happens, the second error will be reported since these
|
|
interfaces always report the most recent result. To avoid
|
|
this, each thread can obtain exclusive use of the <a href="#sqlite3">database connection</a> D
|
|
by invoking <a href="#sqlite3_mutex_alloc">sqlite3_mutex_enter</a>(<a href="#sqlite3_db_mutex">sqlite3_db_mutex</a>(D)) before beginning
|
|
to use D and invoking <a href="#sqlite3_mutex_alloc">sqlite3_mutex_leave</a>(<a href="#sqlite3_db_mutex">sqlite3_db_mutex</a>(D)) after
|
|
all calls to the interfaces listed here are completed.</p>
|
|
|
|
<p>If an interface fails with SQLITE_MISUSE, that means the interface
|
|
was invoked incorrectly by the application. In that case, the
|
|
error code and message may or may not be set.
|
|
</p><hr><a name="sqlite3_expanded_sql"></a>
|
|
<h2>Retrieving Statement SQL</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const char *sqlite3_sql(sqlite3_stmt *pStmt);
|
|
char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
|
|
const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
|
|
SQL text used to create <a href="#sqlite3_stmt">prepared statement</a> P if P was
|
|
created by <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>, <a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>,
|
|
<a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a>, or <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>.
|
|
The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
|
|
string containing the SQL text of prepared statement P with
|
|
<a href="lang_expr.html#varparam">bound parameters</a> expanded.
|
|
The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
|
|
string containing the normalized SQL text of prepared statement P. The
|
|
semantics used to normalize a SQL statement are unspecified and subject
|
|
to change. At a minimum, literal values will be replaced with suitable
|
|
placeholders.</p>
|
|
|
|
<p>For example, if a prepared statement is created using the SQL
|
|
text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
|
|
and parameter :xyz is unbound, then sqlite3_sql() will return
|
|
the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
|
|
will return "SELECT 2345,NULL".</p>
|
|
|
|
<p>The sqlite3_expanded_sql() interface returns NULL if insufficient memory
|
|
is available to hold the result, or if the result would exceed the
|
|
the maximum string length determined by the <a href="#sqlitelimitlength">SQLITE_LIMIT_LENGTH</a>.</p>
|
|
|
|
<p>The <a href="compile.html#trace_size_limit">SQLITE_TRACE_SIZE_LIMIT</a> compile-time option limits the size of
|
|
bound parameter expansions. The <a href="compile.html#omit_trace">SQLITE_OMIT_TRACE</a> compile-time
|
|
option causes sqlite3_expanded_sql() to always return NULL.</p>
|
|
|
|
<p>The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
|
|
are managed by SQLite and are automatically freed when the prepared
|
|
statement is finalized.
|
|
The string returned by sqlite3_expanded_sql(P), on the other hand,
|
|
is obtained from <a href="#sqlite3_free">sqlite3_malloc()</a> and must be free by the application
|
|
by passing it to <a href="#sqlite3_free">sqlite3_free()</a>.
|
|
</p><hr><a name="sqlite3_filename_database"></a>
|
|
<h2>Translate filenames</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const char *sqlite3_filename_database(const char*);
|
|
const char *sqlite3_filename_journal(const char*);
|
|
const char *sqlite3_filename_wal(const char*);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines are available to <a href="vfs.html">custom VFS implementations</a> for
|
|
translating filenames between the main database file, the journal file,
|
|
and the WAL file.</p>
|
|
|
|
<p>If F is the name of an sqlite database file, journal file, or WAL file
|
|
passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
|
|
returns the name of the corresponding database file.</p>
|
|
|
|
<p>If F is the name of an sqlite database file, journal file, or WAL file
|
|
passed by the SQLite core into the VFS, or if F is a database filename
|
|
obtained from <a href="#sqlite3_db_filename">sqlite3_db_filename()</a>, then sqlite3_filename_journal(F)
|
|
returns the name of the corresponding rollback journal file.</p>
|
|
|
|
<p>If F is the name of an sqlite database file, journal file, or WAL file
|
|
that was passed by the SQLite core into the VFS, or if F is a database
|
|
filename obtained from <a href="#sqlite3_db_filename">sqlite3_db_filename()</a>, then
|
|
sqlite3_filename_wal(F) returns the name of the corresponding
|
|
WAL file.</p>
|
|
|
|
<p>In all of the above, if F is not the name of a database, journal or WAL
|
|
filename passed into the VFS from the SQLite core and F is not the
|
|
return value from <a href="#sqlite3_db_filename">sqlite3_db_filename()</a>, then the result is
|
|
undefined and is likely a memory access violation.
|
|
</p><hr><a name="sqlite3_free"></a>
|
|
<h2>Memory Allocation Subsystem</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void *sqlite3_malloc(int);
|
|
void *sqlite3_malloc64(sqlite3_uint64);
|
|
void *sqlite3_realloc(void*, int);
|
|
void *sqlite3_realloc64(void*, sqlite3_uint64);
|
|
void sqlite3_free(void*);
|
|
sqlite3_uint64 sqlite3_msize(void*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The SQLite core uses these three routines for all of its own
|
|
internal memory allocation needs. "Core" in the previous sentence
|
|
does not include operating-system specific <a href="vfs.html">VFS</a> implementation. The
|
|
Windows VFS uses native malloc() and free() for some operations.</p>
|
|
|
|
<p>The sqlite3_malloc() routine returns a pointer to a block
|
|
of memory at least N bytes in length, where N is the parameter.
|
|
If sqlite3_malloc() is unable to obtain sufficient free
|
|
memory, it returns a NULL pointer. If the parameter N to
|
|
sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
|
|
a NULL pointer.</p>
|
|
|
|
<p>The sqlite3_malloc64(N) routine works just like
|
|
sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
|
|
of a signed 32-bit integer.</p>
|
|
|
|
<p>Calling sqlite3_free() with a pointer previously returned
|
|
by sqlite3_malloc() or sqlite3_realloc() releases that memory so
|
|
that it might be reused. The sqlite3_free() routine is
|
|
a no-op if is called with a NULL pointer. Passing a NULL pointer
|
|
to sqlite3_free() is harmless. After being freed, memory
|
|
should neither be read nor written. Even reading previously freed
|
|
memory might result in a segmentation fault or other severe error.
|
|
Memory corruption, a segmentation fault, or other severe error
|
|
might result if sqlite3_free() is called with a non-NULL pointer that
|
|
was not obtained from sqlite3_malloc() or sqlite3_realloc().</p>
|
|
|
|
<p>The sqlite3_realloc(X,N) interface attempts to resize a
|
|
prior memory allocation X to be at least N bytes.
|
|
If the X parameter to sqlite3_realloc(X,N)
|
|
is a NULL pointer then its behavior is identical to calling
|
|
sqlite3_malloc(N).
|
|
If the N parameter to sqlite3_realloc(X,N) is zero or
|
|
negative then the behavior is exactly the same as calling
|
|
sqlite3_free(X).
|
|
sqlite3_realloc(X,N) returns a pointer to a memory allocation
|
|
of at least N bytes in size or NULL if insufficient memory is available.
|
|
If M is the size of the prior allocation, then min(N,M) bytes
|
|
of the prior allocation are copied into the beginning of buffer returned
|
|
by sqlite3_realloc(X,N) and the prior allocation is freed.
|
|
If sqlite3_realloc(X,N) returns NULL and N is positive, then the
|
|
prior allocation is not freed.</p>
|
|
|
|
<p>The sqlite3_realloc64(X,N) interfaces works the same as
|
|
sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
|
|
of a 32-bit signed integer.</p>
|
|
|
|
<p>If X is a memory allocation previously obtained from sqlite3_malloc(),
|
|
sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
|
|
sqlite3_msize(X) returns the size of that memory allocation in bytes.
|
|
The value returned by sqlite3_msize(X) might be larger than the number
|
|
of bytes requested when X was allocated. If X is a NULL pointer then
|
|
sqlite3_msize(X) returns zero. If X points to something that is not
|
|
the beginning of memory allocation, or if it points to a formerly
|
|
valid memory allocation that has now been freed, then the behavior
|
|
of sqlite3_msize(X) is undefined and possibly harmful.</p>
|
|
|
|
<p>The memory returned by sqlite3_malloc(), sqlite3_realloc(),
|
|
sqlite3_malloc64(), and sqlite3_realloc64()
|
|
is always aligned to at least an 8 byte boundary, or to a
|
|
4 byte boundary if the <a href="compile.html#4_byte_aligned_malloc">SQLITE_4_BYTE_ALIGNED_MALLOC</a> compile-time
|
|
option is used.</p>
|
|
|
|
<p>The pointer arguments to <a href="#sqlite3_free">sqlite3_free()</a> and <a href="#sqlite3_free">sqlite3_realloc()</a>
|
|
must be either NULL or else pointers obtained from a prior
|
|
invocation of <a href="#sqlite3_free">sqlite3_malloc()</a> or <a href="#sqlite3_free">sqlite3_realloc()</a> that have
|
|
not yet been released.</p>
|
|
|
|
<p>The application must not read or write any part of
|
|
a block of memory after it has been released using
|
|
<a href="#sqlite3_free">sqlite3_free()</a> or <a href="#sqlite3_free">sqlite3_realloc()</a>.
|
|
</p><hr><a name="sqlite3_free_table"></a>
|
|
<h2>Convenience Routines For Running Queries</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_get_table(
|
|
sqlite3 *db, /* An open database */
|
|
const char *zSql, /* SQL to be evaluated */
|
|
char ***pazResult, /* Results of the query */
|
|
int *pnRow, /* Number of result rows written here */
|
|
int *pnColumn, /* Number of result columns written here */
|
|
char **pzErrmsg /* Error msg written here */
|
|
);
|
|
void sqlite3_free_table(char **result);
|
|
</pre></blockquote>
|
|
<p>
|
|
This is a legacy interface that is preserved for backwards compatibility.
|
|
Use of this interface is not recommended.</p>
|
|
|
|
<p>Definition: A <b>result table</b> is memory data structure created by the
|
|
<a href="#sqlite3_free_table">sqlite3_get_table()</a> interface. A result table records the
|
|
complete query results from one or more queries.</p>
|
|
|
|
<p>The table conceptually has a number of rows and columns. But
|
|
these numbers are not part of the result table itself. These
|
|
numbers are obtained separately. Let N be the number of rows
|
|
and M be the number of columns.</p>
|
|
|
|
<p>A result table is an array of pointers to zero-terminated UTF-8 strings.
|
|
There are (N+1)*M elements in the array. The first M pointers point
|
|
to zero-terminated strings that contain the names of the columns.
|
|
The remaining entries all point to query results. NULL values result
|
|
in NULL pointers. All other values are in their UTF-8 zero-terminated
|
|
string representation as returned by <a href="#sqlite3_column_blob">sqlite3_column_text()</a>.</p>
|
|
|
|
<p>A result table might consist of one or more memory allocations.
|
|
It is not safe to pass a result table directly to <a href="#sqlite3_free">sqlite3_free()</a>.
|
|
A result table should be deallocated using <a href="#sqlite3_free_table">sqlite3_free_table()</a>.</p>
|
|
|
|
<p>As an example of the result table format, suppose a query result
|
|
is as follows:</p>
|
|
|
|
<p><blockquote><pre>
|
|
Name | Age
|
|
-----------------------
|
|
Alice | 43
|
|
Bob | 28
|
|
Cindy | 21
|
|
</pre></blockquote></p>
|
|
|
|
<p>There are two columns (M==2) and three rows (N==3). Thus the
|
|
result table has 8 entries. Suppose the result table is stored
|
|
in an array named azResult. Then azResult holds this content:</p>
|
|
|
|
<p><blockquote><pre>
|
|
azResult[0] = "Name";
|
|
azResult[1] = "Age";
|
|
azResult[2] = "Alice";
|
|
azResult[3] = "43";
|
|
azResult[4] = "Bob";
|
|
azResult[5] = "28";
|
|
azResult[6] = "Cindy";
|
|
azResult[7] = "21";
|
|
</pre></blockquote></p>
|
|
|
|
<p>The sqlite3_get_table() function evaluates one or more
|
|
semicolon-separated SQL statements in the zero-terminated UTF-8
|
|
string of its 2nd parameter and returns a result table to the
|
|
pointer given in its 3rd parameter.</p>
|
|
|
|
<p>After the application has finished with the result from sqlite3_get_table(),
|
|
it must pass the result table pointer to sqlite3_free_table() in order to
|
|
release the memory that was malloced. Because of the way the
|
|
<a href="#sqlite3_free">sqlite3_malloc()</a> happens within sqlite3_get_table(), the calling
|
|
function must not try to call <a href="#sqlite3_free">sqlite3_free()</a> directly. Only
|
|
<a href="#sqlite3_free_table">sqlite3_free_table()</a> is able to release the memory properly and safely.</p>
|
|
|
|
<p>The sqlite3_get_table() interface is implemented as a wrapper around
|
|
<a href="#sqlite3_exec">sqlite3_exec()</a>. The sqlite3_get_table() routine does not have access
|
|
to any internal data structures of SQLite. It uses only the public
|
|
interface defined here. As a consequence, errors that occur in the
|
|
wrapper layer outside of the internal <a href="#sqlite3_exec">sqlite3_exec()</a> call are not
|
|
reflected in subsequent calls to <a href="#sqlite3_errcode">sqlite3_errcode()</a> or
|
|
<a href="#sqlite3_errcode">sqlite3_errmsg()</a>.
|
|
</p><hr><a name="sqlite3_get_auxdata"></a>
|
|
<h2>Function Auxiliary Data</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void *sqlite3_get_auxdata(sqlite3_context*, int N);
|
|
void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
|
|
</pre></blockquote>
|
|
<p>
|
|
These functions may be used by (non-aggregate) SQL functions to
|
|
associate metadata with argument values. If the same value is passed to
|
|
multiple invocations of the same SQL function during query execution, under
|
|
some circumstances the associated metadata may be preserved. An example
|
|
of where this might be useful is in a regular-expression matching
|
|
function. The compiled version of the regular expression can be stored as
|
|
metadata associated with the pattern string.
|
|
Then as long as the pattern string remains the same,
|
|
the compiled regular expression can be reused on multiple
|
|
invocations of the same function.</p>
|
|
|
|
<p>The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
|
|
associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
|
|
value to the application-defined function. N is zero for the left-most
|
|
function argument. If there is no metadata
|
|
associated with the function argument, the sqlite3_get_auxdata(C,N) interface
|
|
returns a NULL pointer.</p>
|
|
|
|
<p>The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
|
|
argument of the application-defined function. Subsequent
|
|
calls to sqlite3_get_auxdata(C,N) return P from the most recent
|
|
sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
|
|
NULL if the metadata has been discarded.
|
|
After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
|
|
SQLite will invoke the destructor function X with parameter P exactly
|
|
once, when the metadata is discarded.
|
|
SQLite is free to discard the metadata at any time, including: <ul>
|
|
<li> when the corresponding function parameter changes, or
|
|
<li> when <a href="#sqlite3_reset">sqlite3_reset()</a> or <a href="#sqlite3_finalize">sqlite3_finalize()</a> is called for the
|
|
SQL statement, or
|
|
<li> when sqlite3_set_auxdata() is invoked again on the same
|
|
parameter, or
|
|
<li> during the original sqlite3_set_auxdata() call when a memory
|
|
allocation error occurs. </ul></p>
|
|
|
|
<p>Note the last bullet in particular. The destructor X in
|
|
sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
|
|
sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata()
|
|
should be called near the end of the function implementation and the
|
|
function implementation should not make any use of P after
|
|
sqlite3_set_auxdata() has been called.</p>
|
|
|
|
<p>In practice, metadata is preserved between function calls for
|
|
function parameters that are compile-time constants, including literal
|
|
values and <a href="lang_expr.html#varparam">parameters</a> and expressions composed from the same.</p>
|
|
|
|
<p>The value of the N parameter to these interfaces should be non-negative.
|
|
Future enhancements may make use of negative N values to define new
|
|
kinds of function caching behavior.</p>
|
|
|
|
<p>These routines must be called from the same thread in which
|
|
the SQL function is running.
|
|
</p><hr><a name="sqlite3_hard_heap_limit64"></a>
|
|
<h2>Impose A Limit On Heap Size</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
|
|
sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
|
|
</pre></blockquote>
|
|
<p>
|
|
These interfaces impose limits on the amount of heap memory that will be
|
|
by all database connections within a single process.</p>
|
|
|
|
<p>The sqlite3_soft_heap_limit64() interface sets and/or queries the
|
|
soft limit on the amount of heap memory that may be allocated by SQLite.
|
|
SQLite strives to keep heap memory utilization below the soft heap
|
|
limit by reducing the number of pages held in the page cache
|
|
as heap memory usages approaches the limit.
|
|
The soft heap limit is "soft" because even though SQLite strives to stay
|
|
below the limit, it will exceed the limit rather than generate
|
|
an <a href="#SQLITE_ABORT">SQLITE_NOMEM</a> error. In other words, the soft heap limit
|
|
is advisory only.</p>
|
|
|
|
<p>The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
|
|
N bytes on the amount of memory that will be allocated. The
|
|
sqlite3_hard_heap_limit64(N) interface is similar to
|
|
sqlite3_soft_heap_limit64(N) except that memory allocations will fail
|
|
when the hard heap limit is reached.</p>
|
|
|
|
<p>The return value from both sqlite3_soft_heap_limit64() and
|
|
sqlite3_hard_heap_limit64() is the size of
|
|
the heap limit prior to the call, or negative in the case of an
|
|
error. If the argument N is negative
|
|
then no change is made to the heap limit. Hence, the current
|
|
size of heap limits can be determined by invoking
|
|
sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).</p>
|
|
|
|
<p>Setting the heap limits to zero disables the heap limiter mechanism.</p>
|
|
|
|
<p>The soft heap limit may not be greater than the hard heap limit.
|
|
If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
|
|
is invoked with a value of N that is greater than the hard heap limit,
|
|
the the soft heap limit is set to the value of the hard heap limit.
|
|
The soft heap limit is automatically enabled whenever the hard heap
|
|
limit is enabled. When sqlite3_hard_heap_limit64(N) is invoked and
|
|
the soft heap limit is outside the range of 1..N, then the soft heap
|
|
limit is set to N. Invoking sqlite3_soft_heap_limit64(0) when the
|
|
hard heap limit is enabled makes the soft heap limit equal to the
|
|
hard heap limit.</p>
|
|
|
|
<p>The memory allocation limits can also be adjusted using
|
|
<a href="pragma.html#pragma_soft_heap_limit">PRAGMA soft_heap_limit</a> and <a href="pragma.html#pragma_hard_heap_limit">PRAGMA hard_heap_limit</a>.</p>
|
|
|
|
<p>The heap limits are not enforced in the current implementation
|
|
if one or more of following conditions are true:</p>
|
|
|
|
<p><ul>
|
|
<li> The limit value is set to zero.
|
|
<li> Memory accounting is disabled using a combination of the
|
|
<a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigmemstatus">SQLITE_CONFIG_MEMSTATUS</a>,...) start-time option and
|
|
the <a href="compile.html#default_memstatus">SQLITE_DEFAULT_MEMSTATUS</a> compile-time option.
|
|
<li> An alternative page cache implementation is specified using
|
|
<a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigpcache2">SQLITE_CONFIG_PCACHE2</a>,...).
|
|
<li> The page cache allocates from its own memory pool supplied
|
|
by <a href="#sqlite3_config">sqlite3_config</a>(<a href="#sqliteconfigpagecache">SQLITE_CONFIG_PAGECACHE</a>,...) rather than
|
|
from the heap.
|
|
</ul></p>
|
|
|
|
<p>The circumstances under which SQLite will enforce the heap limits may
|
|
changes in future releases of SQLite.
|
|
</p><hr><a name="sqlite3_initialize"></a>
|
|
<h2>Initialize The SQLite Library</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_initialize(void);
|
|
int sqlite3_shutdown(void);
|
|
int sqlite3_os_init(void);
|
|
int sqlite3_os_end(void);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_initialize() routine initializes the
|
|
SQLite library. The sqlite3_shutdown() routine
|
|
deallocates any resources that were allocated by sqlite3_initialize().
|
|
These routines are designed to aid in process initialization and
|
|
shutdown on embedded systems. Workstation applications using
|
|
SQLite normally do not need to invoke either of these routines.</p>
|
|
|
|
<p>A call to sqlite3_initialize() is an "effective" call if it is
|
|
the first time sqlite3_initialize() is invoked during the lifetime of
|
|
the process, or if it is the first time sqlite3_initialize() is invoked
|
|
following a call to sqlite3_shutdown(). Only an effective call
|
|
of sqlite3_initialize() does any initialization. All other calls
|
|
are harmless no-ops.</p>
|
|
|
|
<p>A call to sqlite3_shutdown() is an "effective" call if it is the first
|
|
call to sqlite3_shutdown() since the last sqlite3_initialize(). Only
|
|
an effective call to sqlite3_shutdown() does any deinitialization.
|
|
All other valid calls to sqlite3_shutdown() are harmless no-ops.</p>
|
|
|
|
<p>The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
|
|
is not. The sqlite3_shutdown() interface must only be called from a
|
|
single thread. All open <a href="#sqlite3">database connections</a> must be closed and all
|
|
other SQLite resources must be deallocated prior to invoking
|
|
sqlite3_shutdown().</p>
|
|
|
|
<p>Among other things, sqlite3_initialize() will invoke
|
|
sqlite3_os_init(). Similarly, sqlite3_shutdown()
|
|
will invoke sqlite3_os_end().</p>
|
|
|
|
<p>The sqlite3_initialize() routine returns <a href="#SQLITE_ABORT">SQLITE_OK</a> on success.
|
|
If for some reason, sqlite3_initialize() is unable to initialize
|
|
the library (perhaps it is unable to allocate a needed resource such
|
|
as a mutex) it returns an <a href="rescode.html">error code</a> other than <a href="#SQLITE_ABORT">SQLITE_OK</a>.</p>
|
|
|
|
<p>The sqlite3_initialize() routine is called internally by many other
|
|
SQLite interfaces so that an application usually does not need to
|
|
invoke sqlite3_initialize() directly. For example, <a href="#sqlite3_open">sqlite3_open()</a>
|
|
calls sqlite3_initialize() so the SQLite library will be automatically
|
|
initialized when <a href="#sqlite3_open">sqlite3_open()</a> is called if it has not be initialized
|
|
already. However, if SQLite is compiled with the <a href="compile.html#omit_autoinit">SQLITE_OMIT_AUTOINIT</a>
|
|
compile-time option, then the automatic calls to sqlite3_initialize()
|
|
are omitted and the application must call sqlite3_initialize() directly
|
|
prior to using any other SQLite interface. For maximum portability,
|
|
it is recommended that applications always invoke sqlite3_initialize()
|
|
directly prior to using any other SQLite interface. Future releases
|
|
of SQLite may require this. In other words, the behavior exhibited
|
|
when SQLite is compiled with <a href="compile.html#omit_autoinit">SQLITE_OMIT_AUTOINIT</a> might become the
|
|
default behavior in some future release of SQLite.</p>
|
|
|
|
<p>The sqlite3_os_init() routine does operating-system specific
|
|
initialization of the SQLite library. The sqlite3_os_end()
|
|
routine undoes the effect of sqlite3_os_init(). Typical tasks
|
|
performed by these routines include allocation or deallocation
|
|
of static resources, initialization of global variables,
|
|
setting up a default <a href="#sqlite3_vfs">sqlite3_vfs</a> module, or setting up
|
|
a default configuration using <a href="#sqlite3_config">sqlite3_config()</a>.</p>
|
|
|
|
<p>The application should never invoke either sqlite3_os_init()
|
|
or sqlite3_os_end() directly. The application should only invoke
|
|
sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init()
|
|
interface is called automatically by sqlite3_initialize() and
|
|
sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate
|
|
implementations for sqlite3_os_init() and sqlite3_os_end()
|
|
are built into SQLite when it is compiled for Unix, Windows, or OS/2.
|
|
When <a href="custombuild.html">built for other platforms</a>
|
|
(using the <a href="compile.html#os_other">SQLITE_OS_OTHER=1</a> compile-time
|
|
option) the application must supply a suitable implementation for
|
|
sqlite3_os_init() and sqlite3_os_end(). An application-supplied
|
|
implementation of sqlite3_os_init() or sqlite3_os_end()
|
|
must return <a href="#SQLITE_ABORT">SQLITE_OK</a> on success and some other <a href="rescode.html">error code</a> upon
|
|
failure.
|
|
</p><hr><a name="sqlite3_keyword_check"></a>
|
|
<h2>SQL Keyword Checking</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_keyword_count(void);
|
|
int sqlite3_keyword_name(int,const char**,int*);
|
|
int sqlite3_keyword_check(const char*,int);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines provide access to the set of SQL language keywords
|
|
recognized by SQLite. Applications can uses these routines to determine
|
|
whether or not a specific identifier needs to be escaped (for example,
|
|
by enclosing in double-quotes) so as not to confuse the parser.</p>
|
|
|
|
<p>The sqlite3_keyword_count() interface returns the number of distinct
|
|
keywords understood by SQLite.</p>
|
|
|
|
<p>The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and
|
|
makes *Z point to that keyword expressed as UTF8 and writes the number
|
|
of bytes in the keyword into *L. The string that *Z points to is not
|
|
zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns
|
|
SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
|
|
or L are NULL or invalid pointers then calls to
|
|
sqlite3_keyword_name(N,Z,L) result in undefined behavior.</p>
|
|
|
|
<p>The sqlite3_keyword_check(Z,L) interface checks to see whether or not
|
|
the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
|
|
if it is and zero if not.</p>
|
|
|
|
<p>The parser used by SQLite is forgiving. It is often possible to use
|
|
a keyword as an identifier as long as such use does not result in a
|
|
parsing ambiguity. For example, the statement
|
|
"CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
|
|
creates a new table named "BEGIN" with three columns named
|
|
"REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid
|
|
using keywords as identifiers. Common techniques used to avoid keyword
|
|
name collisions include:
|
|
<ul>
|
|
<li> Put all identifier names inside double-quotes. This is the official
|
|
SQL way to escape identifier names.
|
|
<li> Put identifier names inside [...]. This is not standard SQL,
|
|
but it is what SQL Server does and so lots of programmers use this
|
|
technique.
|
|
<li> Begin every identifier with the letter "Z" as no SQL keywords start
|
|
with "Z".
|
|
<li> Include a digit somewhere in every identifier name.
|
|
</ul></p>
|
|
|
|
<p>Note that the number of keywords understood by SQLite can depend on
|
|
compile-time options. For example, "VACUUM" is not a keyword if
|
|
SQLite is compiled with the <a href="compile.html#omit_vacuum">-DSQLITE_OMIT_VACUUM</a> option. Also,
|
|
new keywords may be added to future releases of SQLite.
|
|
</p><hr><a name="sqlite3_libversion"></a>
|
|
<h2>Run-Time Library Version Numbers</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
SQLITE_EXTERN const char sqlite3_version[];
|
|
const char *sqlite3_libversion(void);
|
|
const char *sqlite3_sourceid(void);
|
|
int sqlite3_libversion_number(void);
|
|
</pre></blockquote>
|
|
<p>
|
|
These interfaces provide the same information as the <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION</a>,
|
|
<a href="#SQLITE_SOURCE_ID">SQLITE_VERSION_NUMBER</a>, and <a href="#SQLITE_SOURCE_ID">SQLITE_SOURCE_ID</a> C preprocessor macros
|
|
but are associated with the library instead of the header file. Cautious
|
|
programmers might include assert() statements in their application to
|
|
verify that values returned by these interfaces match the macros in
|
|
the header, and thus ensure that the application is
|
|
compiled with matching library and header files.</p>
|
|
|
|
<p><blockquote><pre>
|
|
assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
|
|
assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
|
|
assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
|
|
</pre></blockquote></p>
|
|
|
|
<p>The sqlite3_version[] string constant contains the text of <a href="#SQLITE_SOURCE_ID">SQLITE_VERSION</a>
|
|
macro. The sqlite3_libversion() function returns a pointer to the
|
|
to the sqlite3_version[] string constant. The sqlite3_libversion()
|
|
function is provided for use in DLLs since DLL users usually do not have
|
|
direct access to string constants within the DLL. The
|
|
sqlite3_libversion_number() function returns an integer equal to
|
|
<a href="#SQLITE_SOURCE_ID">SQLITE_VERSION_NUMBER</a>. The sqlite3_sourceid() function returns
|
|
a pointer to a string constant whose value is the same as the
|
|
<a href="#SQLITE_SOURCE_ID">SQLITE_SOURCE_ID</a> C preprocessor macro. Except if SQLite is built
|
|
using an edited copy of <a href="amalgamation.html">the amalgamation</a>, then the last four characters
|
|
of the hash might be different from <a href="#SQLITE_SOURCE_ID">SQLITE_SOURCE_ID</a>.</p>
|
|
|
|
<p>See also: <a href="lang_corefunc.html#sqlite_version">sqlite_version()</a> and <a href="lang_corefunc.html#sqlite_source_id">sqlite_source_id()</a>.
|
|
</p><hr><a name="sqlite3_memory_highwater"></a>
|
|
<h2>Memory Allocator Statistics</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_int64 sqlite3_memory_used(void);
|
|
sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
|
|
</pre></blockquote>
|
|
<p>
|
|
SQLite provides these two interfaces for reporting on the status
|
|
of the <a href="#sqlite3_free">sqlite3_malloc()</a>, <a href="#sqlite3_free">sqlite3_free()</a>, and <a href="#sqlite3_free">sqlite3_realloc()</a>
|
|
routines, which form the built-in memory allocation subsystem.</p>
|
|
|
|
<p>The <a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a> routine returns the number of bytes
|
|
of memory currently outstanding (malloced but not freed).
|
|
The <a href="#sqlite3_memory_highwater">sqlite3_memory_highwater()</a> routine returns the maximum
|
|
value of <a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a> since the high-water mark
|
|
was last reset. The values returned by <a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a> and
|
|
<a href="#sqlite3_memory_highwater">sqlite3_memory_highwater()</a> include any overhead
|
|
added by SQLite in its implementation of <a href="#sqlite3_free">sqlite3_malloc()</a>,
|
|
but not overhead added by the any underlying system library
|
|
routines that <a href="#sqlite3_free">sqlite3_malloc()</a> may call.</p>
|
|
|
|
<p>The memory high-water mark is reset to the current value of
|
|
<a href="#sqlite3_memory_highwater">sqlite3_memory_used()</a> if and only if the parameter to
|
|
<a href="#sqlite3_memory_highwater">sqlite3_memory_highwater()</a> is true. The value returned
|
|
by <a href="#sqlite3_memory_highwater">sqlite3_memory_highwater(1)</a> is the high-water mark
|
|
prior to the reset.
|
|
</p><hr><a name="sqlite3_mprintf"></a>
|
|
<h2>Formatted String Printing Functions</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
char *sqlite3_mprintf(const char*,...);
|
|
char *sqlite3_vmprintf(const char*, va_list);
|
|
char *sqlite3_snprintf(int,char*,const char*, ...);
|
|
char *sqlite3_vsnprintf(int,char*,const char*, va_list);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines are work-alikes of the "printf()" family of functions
|
|
from the standard C library.
|
|
These routines understand most of the common formatting options from
|
|
the standard library printf()
|
|
plus some additional non-standard formats (<a href="printf.html#percentq">%q</a>, <a href="printf.html#percentq">%Q</a>, <a href="printf.html#percentw">%w</a>, and <a href="printf.html#percentz">%z</a>).
|
|
See the <a href="printf.html">built-in printf()</a> documentation for details.</p>
|
|
|
|
<p>The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
|
|
results into memory obtained from <a href="#sqlite3_free">sqlite3_malloc64()</a>.
|
|
The strings returned by these two routines should be
|
|
released by <a href="#sqlite3_free">sqlite3_free()</a>. Both routines return a
|
|
NULL pointer if <a href="#sqlite3_free">sqlite3_malloc64()</a> is unable to allocate enough
|
|
memory to hold the resulting string.</p>
|
|
|
|
<p>The sqlite3_snprintf() routine is similar to "snprintf()" from
|
|
the standard C library. The result is written into the
|
|
buffer supplied as the second parameter whose size is given by
|
|
the first parameter. Note that the order of the
|
|
first two parameters is reversed from snprintf(). This is an
|
|
historical accident that cannot be fixed without breaking
|
|
backwards compatibility. Note also that sqlite3_snprintf()
|
|
returns a pointer to its buffer instead of the number of
|
|
characters actually written into the buffer. We admit that
|
|
the number of characters written would be a more useful return
|
|
value but we cannot change the implementation of sqlite3_snprintf()
|
|
now without breaking compatibility.</p>
|
|
|
|
<p>As long as the buffer size is greater than zero, sqlite3_snprintf()
|
|
guarantees that the buffer is always zero-terminated. The first
|
|
parameter "n" is the total size of the buffer, including space for
|
|
the zero terminator. So the longest string that can be completely
|
|
written will be n-1 characters.</p>
|
|
|
|
<p>The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().</p>
|
|
|
|
<p>See also: <a href="printf.html">built-in printf()</a>, <a href="lang_corefunc.html#printf">printf() SQL function</a>
|
|
</p><hr><a name="sqlite3_mutex_alloc"></a>
|
|
<h2>Mutexes</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_mutex *sqlite3_mutex_alloc(int);
|
|
void sqlite3_mutex_free(sqlite3_mutex*);
|
|
void sqlite3_mutex_enter(sqlite3_mutex*);
|
|
int sqlite3_mutex_try(sqlite3_mutex*);
|
|
void sqlite3_mutex_leave(sqlite3_mutex*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The SQLite core uses these routines for thread
|
|
synchronization. Though they are intended for internal
|
|
use by SQLite, code that links against SQLite is
|
|
permitted to use any of these routines.</p>
|
|
|
|
<p>The SQLite source code contains multiple implementations
|
|
of these mutex routines. An appropriate implementation
|
|
is selected automatically at compile-time. The following
|
|
implementations are available in the SQLite core:</p>
|
|
|
|
<p><ul>
|
|
<li> SQLITE_MUTEX_PTHREADS
|
|
<li> SQLITE_MUTEX_W32
|
|
<li> SQLITE_MUTEX_NOOP
|
|
</ul></p>
|
|
|
|
<p>The SQLITE_MUTEX_NOOP implementation is a set of routines
|
|
that does no real locking and is appropriate for use in
|
|
a single-threaded application. The SQLITE_MUTEX_PTHREADS and
|
|
SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
|
|
and Windows.</p>
|
|
|
|
<p>If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
|
|
macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
|
|
implementation is included with the library. In this case the
|
|
application must supply a custom mutex implementation using the
|
|
<a href="#sqliteconfigmutex">SQLITE_CONFIG_MUTEX</a> option of the sqlite3_config() function
|
|
before calling sqlite3_initialize() or any other public sqlite3_
|
|
function that calls sqlite3_initialize().</p>
|
|
|
|
<p>The sqlite3_mutex_alloc() routine allocates a new
|
|
mutex and returns a pointer to it. The sqlite3_mutex_alloc()
|
|
routine returns NULL if it is unable to allocate the requested
|
|
mutex. The argument to sqlite3_mutex_alloc() must one of these
|
|
integer constants:</p>
|
|
|
|
<p><ul>
|
|
<li> SQLITE_MUTEX_FAST
|
|
<li> SQLITE_MUTEX_RECURSIVE
|
|
<li> SQLITE_MUTEX_STATIC_MAIN
|
|
<li> SQLITE_MUTEX_STATIC_MEM
|
|
<li> SQLITE_MUTEX_STATIC_OPEN
|
|
<li> SQLITE_MUTEX_STATIC_PRNG
|
|
<li> SQLITE_MUTEX_STATIC_LRU
|
|
<li> SQLITE_MUTEX_STATIC_PMEM
|
|
<li> SQLITE_MUTEX_STATIC_APP1
|
|
<li> SQLITE_MUTEX_STATIC_APP2
|
|
<li> SQLITE_MUTEX_STATIC_APP3
|
|
<li> SQLITE_MUTEX_STATIC_VFS1
|
|
<li> SQLITE_MUTEX_STATIC_VFS2
|
|
<li> SQLITE_MUTEX_STATIC_VFS3
|
|
</ul></p>
|
|
|
|
<p>The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
|
|
cause sqlite3_mutex_alloc() to create
|
|
a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
|
|
is used but not necessarily so when SQLITE_MUTEX_FAST is used.
|
|
The mutex implementation does not need to make a distinction
|
|
between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
|
|
not want to. SQLite will only request a recursive mutex in
|
|
cases where it really needs one. If a faster non-recursive mutex
|
|
implementation is available on the host platform, the mutex subsystem
|
|
might return such a mutex in response to SQLITE_MUTEX_FAST.</p>
|
|
|
|
<p>The other allowed parameters to sqlite3_mutex_alloc() (anything other
|
|
than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
|
|
a pointer to a static preexisting mutex. Nine static mutexes are
|
|
used by the current version of SQLite. Future versions of SQLite
|
|
may add additional static mutexes. Static mutexes are for internal
|
|
use by SQLite only. Applications that use SQLite mutexes should
|
|
use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
|
|
SQLITE_MUTEX_RECURSIVE.</p>
|
|
|
|
<p>Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
|
|
or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
|
|
returns a different mutex on every call. For the static
|
|
mutex types, the same mutex is returned on every call that has
|
|
the same type number.</p>
|
|
|
|
<p>The sqlite3_mutex_free() routine deallocates a previously
|
|
allocated dynamic mutex. Attempting to deallocate a static
|
|
mutex results in undefined behavior.</p>
|
|
|
|
<p>The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
|
|
to enter a mutex. If another thread is already within the mutex,
|
|
sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
|
|
SQLITE_BUSY. The sqlite3_mutex_try() interface returns <a href="#SQLITE_ABORT">SQLITE_OK</a>
|
|
upon successful entry. Mutexes created using
|
|
SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
|
|
In such cases, the
|
|
mutex must be exited an equal number of times before another thread
|
|
can enter. If the same thread tries to enter any mutex other
|
|
than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.</p>
|
|
|
|
<p>Some systems (for example, Windows 95) do not support the operation
|
|
implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try()
|
|
will always return SQLITE_BUSY. The SQLite core only ever uses
|
|
sqlite3_mutex_try() as an optimization so this is acceptable
|
|
behavior.</p>
|
|
|
|
<p>The sqlite3_mutex_leave() routine exits a mutex that was
|
|
previously entered by the same thread. The behavior
|
|
is undefined if the mutex is not currently entered by the
|
|
calling thread or is not currently allocated.</p>
|
|
|
|
<p>If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
|
|
sqlite3_mutex_leave() is a NULL pointer, then all three routines
|
|
behave as no-ops.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_mutex_held">sqlite3_mutex_held()</a> and <a href="#sqlite3_mutex_held">sqlite3_mutex_notheld()</a>.
|
|
</p><hr><a name="sqlite3_mutex_held"></a>
|
|
<h2>Mutex Verification Routines</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#ifndef NDEBUG
|
|
int sqlite3_mutex_held(sqlite3_mutex*);
|
|
int sqlite3_mutex_notheld(sqlite3_mutex*);
|
|
#endif
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
|
|
are intended for use inside assert() statements. The SQLite core
|
|
never uses these routines except inside an assert() and applications
|
|
are advised to follow the lead of the core. The SQLite core only
|
|
provides implementations for these routines when it is compiled
|
|
with the SQLITE_DEBUG flag. External mutex implementations
|
|
are only required to provide these routines if SQLITE_DEBUG is
|
|
defined and if NDEBUG is not defined.</p>
|
|
|
|
<p>These routines should return true if the mutex in their argument
|
|
is held or not held, respectively, by the calling thread.</p>
|
|
|
|
<p>The implementation is not required to provide versions of these
|
|
routines that actually work. If the implementation does not provide working
|
|
versions of these routines, it should at least provide stubs that always
|
|
return true so that one does not get spurious assertion failures.</p>
|
|
|
|
<p>If the argument to sqlite3_mutex_held() is a NULL pointer then
|
|
the routine should return 1. This seems counter-intuitive since
|
|
clearly the mutex cannot be held if it does not exist. But
|
|
the reason the mutex does not exist is because the build is not
|
|
using mutexes. And we do not want the assert() containing the
|
|
call to sqlite3_mutex_held() to fail, so a non-zero return is
|
|
the appropriate thing to do. The sqlite3_mutex_notheld()
|
|
interface should also return 1 when given a NULL pointer.
|
|
</p><hr><a name="sqlite3_open"></a>
|
|
<h2>Opening A New Database Connection</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_open(
|
|
const char *filename, /* Database filename (UTF-8) */
|
|
sqlite3 **ppDb /* OUT: SQLite db handle */
|
|
);
|
|
int sqlite3_open16(
|
|
const void *filename, /* Database filename (UTF-16) */
|
|
sqlite3 **ppDb /* OUT: SQLite db handle */
|
|
);
|
|
int sqlite3_open_v2(
|
|
const char *filename, /* Database filename (UTF-8) */
|
|
sqlite3 **ppDb, /* OUT: SQLite db handle */
|
|
int flags, /* Flags */
|
|
const char *zVfs /* Name of VFS module to use */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines open an SQLite database file as specified by the
|
|
filename argument. The filename argument is interpreted as UTF-8 for
|
|
sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
|
|
order for sqlite3_open16(). A <a href="#sqlite3">database connection</a> handle is usually
|
|
returned in *ppDb, even if an error occurs. The only exception is that
|
|
if SQLite is unable to allocate memory to hold the <a href="#sqlite3">sqlite3</a> object,
|
|
a NULL will be written into *ppDb instead of a pointer to the <a href="#sqlite3">sqlite3</a>
|
|
object. If the database is opened (and/or created) successfully, then
|
|
<a href="#SQLITE_ABORT">SQLITE_OK</a> is returned. Otherwise an <a href="rescode.html">error code</a> is returned. The
|
|
<a href="#sqlite3_errcode">sqlite3_errmsg()</a> or <a href="#sqlite3_errcode">sqlite3_errmsg16()</a> routines can be used to obtain
|
|
an English language description of the error following a failure of any
|
|
of the sqlite3_open() routines.</p>
|
|
|
|
<p>The default encoding will be UTF-8 for databases created using
|
|
sqlite3_open() or sqlite3_open_v2(). The default encoding for databases
|
|
created using sqlite3_open16() will be UTF-16 in the native byte order.</p>
|
|
|
|
<p>Whether or not an error occurs when it is opened, resources
|
|
associated with the <a href="#sqlite3">database connection</a> handle should be released by
|
|
passing it to <a href="#sqlite3_close">sqlite3_close()</a> when it is no longer required.</p>
|
|
|
|
<p>The sqlite3_open_v2() interface works like sqlite3_open()
|
|
except that it accepts two additional parameters for additional control
|
|
over the new database connection. The flags parameter to
|
|
sqlite3_open_v2() must include, at a minimum, one of the following
|
|
three flag combinations:</p>
|
|
|
|
<p><dl>
|
|
<dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READONLY</a></dt>
|
|
<dd>The database is opened in read-only mode. If the database does not
|
|
already exist, an error is returned.</dd></p>
|
|
|
|
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READWRITE</a></dt>
|
|
<dd>The database is opened for reading and writing if possible, or reading
|
|
only if the file is write protected by the operating system. In either
|
|
case the database must already exist, otherwise an error is returned.</dd></p>
|
|
|
|
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READWRITE</a> | <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_CREATE</a></dt>
|
|
<dd>The database is opened for reading and writing, and is created if
|
|
it does not already exist. This is the behavior that is always used for
|
|
sqlite3_open() and sqlite3_open16().</dd>
|
|
</dl></p>
|
|
|
|
<p>In addition to the required flags, the following optional flags are
|
|
also supported:</p>
|
|
|
|
<p><dl>
|
|
<dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_URI</a></dt>
|
|
<dd>The filename can be interpreted as a URI if this flag is set.</dd></p>
|
|
|
|
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_MEMORY</a></dt>
|
|
<dd>The database will be opened as an in-memory database. The database
|
|
is named by the "filename" argument for the purposes of cache-sharing,
|
|
if shared cache mode is enabled, but the "filename" is otherwise ignored.
|
|
</dd></p>
|
|
|
|
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_NOMUTEX</a></dt>
|
|
<dd>The new database connection will use the "multi-thread"
|
|
<a href="threadsafe.html">threading mode</a>. This means that separate threads are allowed
|
|
to use SQLite at the same time, as long as each thread is using
|
|
a different <a href="#sqlite3">database connection</a>.</p>
|
|
|
|
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_FULLMUTEX</a></dt>
|
|
<dd>The new database connection will use the "serialized"
|
|
<a href="threadsafe.html">threading mode</a>. This means the multiple threads can safely
|
|
attempt to use the same database connection at the same time.
|
|
(Mutexes will block any actual concurrency, but in this mode
|
|
there is no harm in trying.)</p>
|
|
|
|
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_SHAREDCACHE</a></dt>
|
|
<dd>The database is opened <a href="sharedcache.html">shared cache</a> enabled, overriding
|
|
the default shared cache setting provided by
|
|
<a href="#sqlite3_enable_shared_cache">sqlite3_enable_shared_cache()</a>.</p>
|
|
|
|
<p><dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_PRIVATECACHE</a></dt>
|
|
<dd>The database is opened <a href="sharedcache.html">shared cache</a> disabled, overriding
|
|
the default shared cache setting provided by
|
|
<a href="#sqlite3_enable_shared_cache">sqlite3_enable_shared_cache()</a>.</p>
|
|
|
|
<p><a name="opennofollow"></a>
|
|
<dt><a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_NOFOLLOW</a></dt>
|
|
<dd>The database filename is not allowed to be a symbolic link</dd>
|
|
</dl></p>
|
|
|
|
<p>If the 3rd parameter to sqlite3_open_v2() is not one of the
|
|
required combinations shown above optionally combined with other
|
|
<a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_* bits</a>
|
|
then the behavior is undefined.</p>
|
|
|
|
<p>The fourth parameter to sqlite3_open_v2() is the name of the
|
|
<a href="#sqlite3_vfs">sqlite3_vfs</a> object that defines the operating system interface that
|
|
the new database connection should use. If the fourth parameter is
|
|
a NULL pointer then the default <a href="#sqlite3_vfs">sqlite3_vfs</a> object is used.</p>
|
|
|
|
<p>If the filename is ":memory:", then a private, temporary in-memory database
|
|
is created for the connection. This in-memory database will vanish when
|
|
the database connection is closed. Future versions of SQLite might
|
|
make use of additional special filenames that begin with the ":" character.
|
|
It is recommended that when a database filename actually does begin with
|
|
a ":" character you should prefix the filename with a pathname such as
|
|
"./" to avoid ambiguity.</p>
|
|
|
|
<p>If the filename is an empty string, then a private, temporary
|
|
on-disk database will be created. This private database will be
|
|
automatically deleted as soon as the database connection is closed.</p>
|
|
|
|
<p><a name="urifilenamesinsqlite3open"></a>
|
|
<h3>URI Filenames</h3></p>
|
|
|
|
<p>If <a href="uri.html">URI filename</a> interpretation is enabled, and the filename argument
|
|
begins with "file:", then the filename is interpreted as a URI. URI
|
|
filename interpretation is enabled if the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_URI</a> flag is
|
|
set in the third argument to sqlite3_open_v2(), or if it has
|
|
been enabled globally using the <a href="#sqliteconfiguri">SQLITE_CONFIG_URI</a> option with the
|
|
<a href="#sqlite3_config">sqlite3_config()</a> method or by the <a href="compile.html#use_uri">SQLITE_USE_URI</a> compile-time option.
|
|
URI filename interpretation is turned off
|
|
by default, but future releases of SQLite might enable URI filename
|
|
interpretation by default. See "<a href="uri.html">URI filenames</a>" for additional
|
|
information.</p>
|
|
|
|
<p>URI filenames are parsed according to RFC 3986. If the URI contains an
|
|
authority, then it must be either an empty string or the string
|
|
"localhost". If the authority is not an empty string or "localhost", an
|
|
error is returned to the caller. The fragment component of a URI, if
|
|
present, is ignored.</p>
|
|
|
|
<p>SQLite uses the path component of the URI as the name of the disk file
|
|
which contains the database. If the path begins with a '/' character,
|
|
then it is interpreted as an absolute path. If the path does not begin
|
|
with a '/' (meaning that the authority section is omitted from the URI)
|
|
then the path is interpreted as a relative path.
|
|
On windows, the first component of an absolute path
|
|
is a drive specification (e.g. "C:").</p>
|
|
|
|
<p><a name="coreuriqueryparameters"></a>
|
|
|
|
The query component of a URI may contain parameters that are interpreted
|
|
either by SQLite itself, or by a <a href="vfs.html">custom VFS implementation</a>.
|
|
SQLite and its built-in <a href="vfs.html">VFSes</a> interpret the
|
|
following query parameters:</p>
|
|
|
|
<p><ul>
|
|
<li> <b>vfs</b>: The "vfs" parameter may be used to specify the name of
|
|
a VFS object that provides the operating system interface that should
|
|
be used to access the database file on disk. If this option is set to
|
|
an empty string the default VFS object is used. Specifying an unknown
|
|
VFS is an error. If sqlite3_open_v2() is used and the vfs option is
|
|
present, then the VFS specified by the option takes precedence over
|
|
the value passed as the fourth parameter to sqlite3_open_v2().</p>
|
|
|
|
<p><li> <b>mode</b>: The mode parameter may be set to either "ro", "rw",
|
|
"rwc", or "memory". Attempting to set it to any other value is
|
|
an error.
|
|
If "ro" is specified, then the database is opened for read-only
|
|
access, just as if the <a href="#SQLITE_OPEN_AUTOPROXY">SQLITE_OPEN_READONLY</a> flag had been set in the
|
|
third argument to sqlite3_open_v2(). If the mode option is set to
|
|
"rw", then the database is opened for read-write (but not create)
|
|
access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
|
|
been set. Value "rwc" is equivalent to setting both
|
|
SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. If the mode option is
|
|
set to "memory" then a pure <a href="inmemorydb.html">in-memory database</a> that never reads
|
|
or writes from disk is used. It is an error to specify a value for
|
|
the mode parameter that is less restrictive than that specified by
|
|
the flags passed in the third parameter to sqlite3_open_v2().</p>
|
|
|
|
<p><li> <b>cache</b>: The cache parameter may be set to either "shared" or
|
|
"private". Setting it to "shared" is equivalent to setting the
|
|
SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
|
|
sqlite3_open_v2(). Setting the cache parameter to "private" is
|
|
equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
|
|
If sqlite3_open_v2() is used and the "cache" parameter is present in
|
|
a URI filename, its value overrides any behavior requested by setting
|
|
SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.</p>
|
|
|
|
<p><li> <b>psow</b>: The psow parameter indicates whether or not the
|
|
<a href="psow.html">powersafe overwrite</a> property does or does not apply to the
|
|
storage media on which the database file resides.</p>
|
|
|
|
<p><li> <b>nolock</b>: The nolock parameter is a boolean query parameter
|
|
which if set disables file locking in rollback journal modes. This
|
|
is useful for accessing a database on a filesystem that does not
|
|
support locking. Caution: Database corruption might result if two
|
|
or more processes write to the same database and any one of those
|
|
processes uses nolock=1.</p>
|
|
|
|
<p><li> <b>immutable</b>: The immutable parameter is a boolean query
|
|
parameter that indicates that the database file is stored on
|
|
read-only media. When immutable is set, SQLite assumes that the
|
|
database file cannot be changed, even by a process with higher
|
|
privilege, and so the database is opened read-only and all locking
|
|
and change detection is disabled. Caution: Setting the immutable
|
|
property on a database file that does in fact change can result
|
|
in incorrect query results and/or <a href="#SQLITE_ABORT">SQLITE_CORRUPT</a> errors.
|
|
See also: <a href="#SQLITE_IOCAP_ATOMIC">SQLITE_IOCAP_IMMUTABLE</a>.</p>
|
|
|
|
<p></ul></p>
|
|
|
|
<p>Specifying an unknown parameter in the query component of a URI is not an
|
|
error. Future versions of SQLite might understand additional query
|
|
parameters. See "<a href="uri.html#coreqp">query parameters with special meaning to SQLite</a>" for
|
|
additional information.</p>
|
|
|
|
<p><a name="urifilenameexamples"></a>
|
|
<h3>URI filename examples</h3></p>
|
|
|
|
<p><table border="1" align=center cellpadding=5>
|
|
<tr><th> URI filenames <th> Results
|
|
<tr><td> file:data.db <td>
|
|
Open the file "data.db" in the current directory.
|
|
<tr><td> file:/home/fred/data.db<br>
|
|
file:///home/fred/data.db <br>
|
|
file://localhost/home/fred/data.db <br> <td>
|
|
Open the database file "/home/fred/data.db".
|
|
<tr><td> file://darkstar/home/fred/data.db <td>
|
|
An error. "darkstar" is not a recognized authority.
|
|
<tr><td style="white-space:nowrap">
|
|
file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
|
|
<td> Windows only: Open the file "data.db" on fred's desktop on drive
|
|
C:. Note that the %20 escaping in this example is not strictly
|
|
necessary - space characters can be used literally
|
|
in URI filenames.
|
|
<tr><td> file:data.db?mode=ro&cache=private <td>
|
|
Open file "data.db" in the current directory for read-only access.
|
|
Regardless of whether or not shared-cache mode is enabled by
|
|
default, use a private cache.
|
|
<tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
|
|
Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
|
|
that uses dot-files in place of posix advisory locking.
|
|
<tr><td> file:data.db?mode=readonly <td>
|
|
An error. "readonly" is not a valid option for the "mode" parameter.
|
|
</table></p>
|
|
|
|
<p>URI hexadecimal escape sequences (%HH) are supported within the path and
|
|
query components of a URI. A hexadecimal escape sequence consists of a
|
|
percent sign - "%" - followed by exactly two hexadecimal digits
|
|
specifying an octet value. Before the path or query components of a
|
|
URI filename are interpreted, they are encoded using UTF-8 and all
|
|
hexadecimal escape sequences replaced by a single byte containing the
|
|
corresponding octet. If this process generates an invalid UTF-8 encoding,
|
|
the results are undefined.</p>
|
|
|
|
<p><b>Note to Windows users:</b> The encoding used for the filename argument
|
|
of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
|
|
codepage is currently defined. Filenames containing international
|
|
characters must be converted to UTF-8 prior to passing them into
|
|
sqlite3_open() or sqlite3_open_v2().</p>
|
|
|
|
<p><b>Note to Windows Runtime users:</b> The temporary directory must be set
|
|
prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various
|
|
features that require the use of temporary files may fail.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_temp_directory">sqlite3_temp_directory</a>
|
|
</p><hr><a name="sqlite3_preupdate_count"></a>
|
|
<h2>The pre-update hook.</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
|
|
void *sqlite3_preupdate_hook(
|
|
sqlite3 *db,
|
|
void(*xPreUpdate)(
|
|
void *pCtx, /* Copy of third arg to preupdate_hook() */
|
|
sqlite3 *db, /* Database handle */
|
|
int op, /* SQLITE_UPDATE, DELETE or INSERT */
|
|
char const *zDb, /* Database name */
|
|
char const *zName, /* Table name */
|
|
sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */
|
|
sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */
|
|
),
|
|
void*
|
|
);
|
|
int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
|
|
int sqlite3_preupdate_count(sqlite3 *);
|
|
int sqlite3_preupdate_depth(sqlite3 *);
|
|
int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
|
|
#endif
|
|
</pre></blockquote>
|
|
<p>
|
|
These interfaces are only available if SQLite is compiled using the
|
|
<a href="compile.html#enable_preupdate_hook">SQLITE_ENABLE_PREUPDATE_HOOK</a> compile-time option.</p>
|
|
|
|
<p>The <a href="#sqlite3_preupdate_count">sqlite3_preupdate_hook()</a> interface registers a callback function
|
|
that is invoked prior to each <a href="lang_insert.html">INSERT</a>, <a href="lang_update.html">UPDATE</a>, and <a href="lang_delete.html">DELETE</a> operation
|
|
on a database table.
|
|
At most one preupdate hook may be registered at a time on a single
|
|
<a href="#sqlite3">database connection</a>; each call to <a href="#sqlite3_preupdate_count">sqlite3_preupdate_hook()</a> overrides
|
|
the previous setting.
|
|
The preupdate hook is disabled by invoking <a href="#sqlite3_preupdate_count">sqlite3_preupdate_hook()</a>
|
|
with a NULL pointer as the second parameter.
|
|
The third parameter to <a href="#sqlite3_preupdate_count">sqlite3_preupdate_hook()</a> is passed through as
|
|
the first parameter to callbacks.</p>
|
|
|
|
<p>The preupdate hook only fires for changes to real database tables; the
|
|
preupdate hook is not invoked for changes to <a href="vtab.html">virtual tables</a> or to
|
|
system tables like sqlite_sequence or sqlite_stat1.</p>
|
|
|
|
<p>The second parameter to the preupdate callback is a pointer to
|
|
the <a href="#sqlite3">database connection</a> that registered the preupdate hook.
|
|
The third parameter to the preupdate callback is one of the constants
|
|
<a href="#SQLITE_ALTER_TABLE">SQLITE_INSERT</a>, <a href="#SQLITE_ALTER_TABLE">SQLITE_DELETE</a>, or <a href="#SQLITE_ALTER_TABLE">SQLITE_UPDATE</a> to identify the
|
|
kind of update operation that is about to occur.
|
|
The fourth parameter to the preupdate callback is the name of the
|
|
database within the database connection that is being modified. This
|
|
will be "main" for the main database or "temp" for TEMP tables or
|
|
the name given after the AS keyword in the <a href="lang_attach.html">ATTACH</a> statement for attached
|
|
databases.
|
|
The fifth parameter to the preupdate callback is the name of the
|
|
table that is being modified.</p>
|
|
|
|
<p>For an UPDATE or DELETE operation on a <a href="rowidtable.html">rowid table</a>, the sixth
|
|
parameter passed to the preupdate callback is the initial <a href="lang_createtable.html#rowid">rowid</a> of the
|
|
row being modified or deleted. For an INSERT operation on a rowid table,
|
|
or any operation on a WITHOUT ROWID table, the value of the sixth
|
|
parameter is undefined. For an INSERT or UPDATE on a rowid table the
|
|
seventh parameter is the final rowid value of the row being inserted
|
|
or updated. The value of the seventh parameter passed to the callback
|
|
function is not defined for operations on WITHOUT ROWID tables, or for
|
|
INSERT operations on rowid tables.</p>
|
|
|
|
<p>The <a href="#sqlite3_preupdate_count">sqlite3_preupdate_old()</a>, <a href="#sqlite3_preupdate_count">sqlite3_preupdate_new()</a>,
|
|
<a href="#sqlite3_preupdate_count">sqlite3_preupdate_count()</a>, and <a href="#sqlite3_preupdate_count">sqlite3_preupdate_depth()</a> interfaces
|
|
provide additional information about a preupdate event. These routines
|
|
may only be called from within a preupdate callback. Invoking any of
|
|
these routines from outside of a preupdate callback or with a
|
|
<a href="#sqlite3">database connection</a> pointer that is different from the one supplied
|
|
to the preupdate callback results in undefined and probably undesirable
|
|
behavior.</p>
|
|
|
|
<p>The <a href="#sqlite3_preupdate_count">sqlite3_preupdate_count(D)</a> interface returns the number of columns
|
|
in the row that is being inserted, updated, or deleted.</p>
|
|
|
|
<p>The <a href="#sqlite3_preupdate_count">sqlite3_preupdate_old(D,N,P)</a> interface writes into P a pointer to
|
|
a <a href="#sqlite3_value">protected sqlite3_value</a> that contains the value of the Nth column of
|
|
the table row before it is updated. The N parameter must be between 0
|
|
and one less than the number of columns or the behavior will be
|
|
undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
|
|
preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
|
|
behavior is undefined. The <a href="#sqlite3_value">sqlite3_value</a> that P points to
|
|
will be destroyed when the preupdate callback returns.</p>
|
|
|
|
<p>The <a href="#sqlite3_preupdate_count">sqlite3_preupdate_new(D,N,P)</a> interface writes into P a pointer to
|
|
a <a href="#sqlite3_value">protected sqlite3_value</a> that contains the value of the Nth column of
|
|
the table row after it is updated. The N parameter must be between 0
|
|
and one less than the number of columns or the behavior will be
|
|
undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
|
|
preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
|
|
behavior is undefined. The <a href="#sqlite3_value">sqlite3_value</a> that P points to
|
|
will be destroyed when the preupdate callback returns.</p>
|
|
|
|
<p>The <a href="#sqlite3_preupdate_count">sqlite3_preupdate_depth(D)</a> interface returns 0 if the preupdate
|
|
callback was invoked as a result of a direct insert, update, or delete
|
|
operation; or 1 for inserts, updates, or deletes invoked by top-level
|
|
triggers; or 2 for changes resulting from triggers called by top-level
|
|
triggers; and so forth.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_update_hook">sqlite3_update_hook()</a>
|
|
</p><hr><a name="sqlite3_profile"></a>
|
|
<h2>Tracing And Profiling Functions</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void *sqlite3_trace(sqlite3*,
|
|
void(*xTrace)(void*,const char*), void*);
|
|
void *sqlite3_profile(sqlite3*,
|
|
void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines are deprecated. Use the <a href="#sqlite3_trace_v2">sqlite3_trace_v2()</a> interface
|
|
instead of the routines described here.</p>
|
|
|
|
<p>These routines register callback functions that can be used for
|
|
tracing and profiling the execution of SQL statements.</p>
|
|
|
|
<p>The callback function registered by sqlite3_trace() is invoked at
|
|
various times when an SQL statement is being run by <a href="#sqlite3_step">sqlite3_step()</a>.
|
|
The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
|
|
SQL statement text as the statement first begins executing.
|
|
Additional sqlite3_trace() callbacks might occur
|
|
as each triggered subprogram is entered. The callbacks for triggers
|
|
contain a UTF-8 SQL comment that identifies the trigger.</p>
|
|
|
|
<p>The <a href="compile.html#trace_size_limit">SQLITE_TRACE_SIZE_LIMIT</a> compile-time option can be used to limit
|
|
the length of <a href="lang_expr.html#varparam">bound parameter</a> expansion in the output of sqlite3_trace().</p>
|
|
|
|
<p>The callback function registered by sqlite3_profile() is invoked
|
|
as each SQL statement finishes. The profile callback contains
|
|
the original statement text and an estimate of wall-clock time
|
|
of how long that statement took to run. The profile callback
|
|
time is in units of nanoseconds, however the current implementation
|
|
is only capable of millisecond resolution so the six least significant
|
|
digits in the time are meaningless. Future versions of SQLite
|
|
might provide greater resolution on the profiler callback. Invoking
|
|
either <a href="#sqlite3_profile">sqlite3_trace()</a> or <a href="#sqlite3_trace_v2">sqlite3_trace_v2()</a> will cancel the
|
|
profile callback.
|
|
</p><hr><a name="sqlite3_result_blob"></a>
|
|
<h2>Setting The Result Of An SQL Function</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
|
|
void sqlite3_result_blob64(sqlite3_context*,const void*,
|
|
sqlite3_uint64,void(*)(void*));
|
|
void sqlite3_result_double(sqlite3_context*, double);
|
|
void sqlite3_result_error(sqlite3_context*, const char*, int);
|
|
void sqlite3_result_error16(sqlite3_context*, const void*, int);
|
|
void sqlite3_result_error_toobig(sqlite3_context*);
|
|
void sqlite3_result_error_nomem(sqlite3_context*);
|
|
void sqlite3_result_error_code(sqlite3_context*, int);
|
|
void sqlite3_result_int(sqlite3_context*, int);
|
|
void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
|
|
void sqlite3_result_null(sqlite3_context*);
|
|
void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
|
|
void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
|
|
void(*)(void*), unsigned char encoding);
|
|
void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
|
|
void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
|
|
void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
|
|
void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
|
|
void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
|
|
void sqlite3_result_zeroblob(sqlite3_context*, int n);
|
|
int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
|
|
</pre></blockquote>
|
|
<p>
|
|
These routines are used by the xFunc or xFinal callbacks that
|
|
implement SQL functions and aggregates. See
|
|
<a href="#sqlite3_create_function">sqlite3_create_function()</a> and <a href="#sqlite3_create_function">sqlite3_create_function16()</a>
|
|
for additional information.</p>
|
|
|
|
<p>These functions work very much like the <a href="#sqlite3_bind_blob">parameter binding</a> family of
|
|
functions used to bind values to host parameters in prepared statements.
|
|
Refer to the <a href="#sqlite3_bind_blob">SQL parameter</a> documentation for additional information.</p>
|
|
|
|
<p>The sqlite3_result_blob() interface sets the result from
|
|
an application-defined function to be the BLOB whose content is pointed
|
|
to by the second parameter and which is N bytes long where N is the
|
|
third parameter.</p>
|
|
|
|
<p>The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
|
|
interfaces set the result of the application-defined function to be
|
|
a BLOB containing all zero bytes and N bytes in size.</p>
|
|
|
|
<p>The sqlite3_result_double() interface sets the result from
|
|
an application-defined function to be a floating point value specified
|
|
by its 2nd argument.</p>
|
|
|
|
<p>The sqlite3_result_error() and sqlite3_result_error16() functions
|
|
cause the implemented SQL function to throw an exception.
|
|
SQLite uses the string pointed to by the
|
|
2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
|
|
as the text of an error message. SQLite interprets the error
|
|
message string from sqlite3_result_error() as UTF-8. SQLite
|
|
interprets the string from sqlite3_result_error16() as UTF-16 using
|
|
the same <a href="#byteorderdeterminationrules">byte-order determination rules</a> as <a href="#sqlite3_bind_blob">sqlite3_bind_text16()</a>.
|
|
If the third parameter to sqlite3_result_error()
|
|
or sqlite3_result_error16() is negative then SQLite takes as the error
|
|
message all text up through the first zero character.
|
|
If the third parameter to sqlite3_result_error() or
|
|
sqlite3_result_error16() is non-negative then SQLite takes that many
|
|
bytes (not characters) from the 2nd parameter as the error message.
|
|
The sqlite3_result_error() and sqlite3_result_error16()
|
|
routines make a private copy of the error message text before
|
|
they return. Hence, the calling function can deallocate or
|
|
modify the text after they return without harm.
|
|
The sqlite3_result_error_code() function changes the error code
|
|
returned by SQLite as a result of an error in a function. By default,
|
|
the error code is SQLITE_ERROR. A subsequent call to sqlite3_result_error()
|
|
or sqlite3_result_error16() resets the error code to SQLITE_ERROR.</p>
|
|
|
|
<p>The sqlite3_result_error_toobig() interface causes SQLite to throw an
|
|
error indicating that a string or BLOB is too long to represent.</p>
|
|
|
|
<p>The sqlite3_result_error_nomem() interface causes SQLite to throw an
|
|
error indicating that a memory allocation failed.</p>
|
|
|
|
<p>The sqlite3_result_int() interface sets the return value
|
|
of the application-defined function to be the 32-bit signed integer
|
|
value given in the 2nd argument.
|
|
The sqlite3_result_int64() interface sets the return value
|
|
of the application-defined function to be the 64-bit signed integer
|
|
value given in the 2nd argument.</p>
|
|
|
|
<p>The sqlite3_result_null() interface sets the return value
|
|
of the application-defined function to be NULL.</p>
|
|
|
|
<p>The sqlite3_result_text(), sqlite3_result_text16(),
|
|
sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
|
|
set the return value of the application-defined function to be
|
|
a text string which is represented as UTF-8, UTF-16 native byte order,
|
|
UTF-16 little endian, or UTF-16 big endian, respectively.
|
|
The sqlite3_result_text64() interface sets the return value of an
|
|
application-defined function to be a text string in an encoding
|
|
specified by the fifth (and last) parameter, which must be one
|
|
of <a href="#SQLITE_ANY">SQLITE_UTF8</a>, <a href="#SQLITE_ANY">SQLITE_UTF16</a>, <a href="#SQLITE_ANY">SQLITE_UTF16BE</a>, or <a href="#SQLITE_ANY">SQLITE_UTF16LE</a>.
|
|
SQLite takes the text result from the application from
|
|
the 2nd parameter of the sqlite3_result_text* interfaces.
|
|
If the 3rd parameter to the sqlite3_result_text* interfaces
|
|
is negative, then SQLite takes result text from the 2nd parameter
|
|
through the first zero character.
|
|
If the 3rd parameter to the sqlite3_result_text* interfaces
|
|
is non-negative, then as many bytes (not characters) of the text
|
|
pointed to by the 2nd parameter are taken as the application-defined
|
|
function result. If the 3rd parameter is non-negative, then it
|
|
must be the byte offset into the string where the NUL terminator would
|
|
appear if the string where NUL terminated. If any NUL characters occur
|
|
in the string at a byte offset that is less than the value of the 3rd
|
|
parameter, then the resulting string will contain embedded NULs and the
|
|
result of expressions operating on strings with embedded NULs is undefined.
|
|
If the 4th parameter to the sqlite3_result_text* interfaces
|
|
or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
|
|
function as the destructor on the text or BLOB result when it has
|
|
finished using that result.
|
|
If the 4th parameter to the sqlite3_result_text* interfaces or to
|
|
sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
|
|
assumes that the text or BLOB result is in constant space and does not
|
|
copy the content of the parameter nor call a destructor on the content
|
|
when it has finished using that result.
|
|
If the 4th parameter to the sqlite3_result_text* interfaces
|
|
or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
|
|
then SQLite makes a copy of the result into space obtained
|
|
from <a href="#sqlite3_free">sqlite3_malloc()</a> before it returns.</p>
|
|
|
|
<p>For the sqlite3_result_text16(), sqlite3_result_text16le(), and
|
|
sqlite3_result_text16be() routines, and for sqlite3_result_text64()
|
|
when the encoding is not UTF8, if the input UTF16 begins with a
|
|
byte-order mark (BOM, U+FEFF) then the BOM is removed from the
|
|
string and the rest of the string is interpreted according to the
|
|
byte-order specified by the BOM. The byte-order specified by
|
|
the BOM at the beginning of the text overrides the byte-order
|
|
specified by the interface procedure. So, for example, if
|
|
sqlite3_result_text16le() is invoked with text that begins
|
|
with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
|
|
first two bytes of input are skipped and the remaining input
|
|
is interpreted as UTF16BE text.</p>
|
|
|
|
<p>For UTF16 input text to the sqlite3_result_text16(),
|
|
sqlite3_result_text16be(), sqlite3_result_text16le(), and
|
|
sqlite3_result_text64() routines, if the text contains invalid
|
|
UTF16 characters, the invalid characters might be converted
|
|
into the unicode replacement character, U+FFFD.</p>
|
|
|
|
<p>The sqlite3_result_value() interface sets the result of
|
|
the application-defined function to be a copy of the
|
|
<a href="#sqlite3_value">unprotected sqlite3_value</a> object specified by the 2nd parameter. The
|
|
sqlite3_result_value() interface makes a copy of the <a href="#sqlite3_value">sqlite3_value</a>
|
|
so that the <a href="#sqlite3_value">sqlite3_value</a> specified in the parameter may change or
|
|
be deallocated after sqlite3_result_value() returns without harm.
|
|
A <a href="#sqlite3_value">protected sqlite3_value</a> object may always be used where an
|
|
<a href="#sqlite3_value">unprotected sqlite3_value</a> object is required, so either
|
|
kind of <a href="#sqlite3_value">sqlite3_value</a> object can be used with this interface.</p>
|
|
|
|
<p>The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
|
|
SQL NULL value, just like <a href="#sqlite3_result_blob">sqlite3_result_null(C)</a>, except that it
|
|
also associates the host-language pointer P or type T with that
|
|
NULL value such that the pointer can be retrieved within an
|
|
<a href="appfunc.html">application-defined SQL function</a> using <a href="#sqlite3_value_blob">sqlite3_value_pointer()</a>.
|
|
If the D parameter is not NULL, then it is a pointer to a destructor
|
|
for the P parameter. SQLite invokes D with P as its only argument
|
|
when SQLite is finished with P. The T parameter should be a static
|
|
string and preferably a string literal. The sqlite3_result_pointer()
|
|
routine is part of the <a href="bindptr.html">pointer passing interface</a> added for SQLite 3.20.0.</p>
|
|
|
|
<p>If these routines are called from within the different thread
|
|
than the one containing the application-defined function that received
|
|
the <a href="#sqlite3_context">sqlite3_context</a> pointer, the results are undefined.
|
|
</p><hr><a name="sqlite3_status"></a>
|
|
<h2>SQLite Runtime Status</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
|
|
int sqlite3_status64(
|
|
int op,
|
|
sqlite3_int64 *pCurrent,
|
|
sqlite3_int64 *pHighwater,
|
|
int resetFlag
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
These interfaces are used to retrieve runtime status information
|
|
about the performance of SQLite, and optionally to reset various
|
|
highwater marks. The first argument is an integer code for
|
|
the specific parameter to measure. Recognized integer codes
|
|
are of the form <a href="#SQLITE_STATUS_MALLOC_COUNT">SQLITE_STATUS_...</a>.
|
|
The current value of the parameter is returned into *pCurrent.
|
|
The highest recorded value is returned in *pHighwater. If the
|
|
resetFlag is true, then the highest record value is reset after
|
|
*pHighwater is written. Some parameters do not record the highest
|
|
value. For those parameters
|
|
nothing is written into *pHighwater and the resetFlag is ignored.
|
|
Other parameters record only the highwater mark and not the current
|
|
value. For these latter parameters nothing is written into *pCurrent.</p>
|
|
|
|
<p>The sqlite3_status() and sqlite3_status64() routines return
|
|
SQLITE_OK on success and a non-zero <a href="rescode.html">error code</a> on failure.</p>
|
|
|
|
<p>If either the current value or the highwater mark is too large to
|
|
be represented by a 32-bit integer, then the values returned by
|
|
sqlite3_status() are undefined.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_db_status">sqlite3_db_status()</a>
|
|
</p><hr><a name="sqlite3_str_append"></a>
|
|
<h2>Add Content To A Dynamic String</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
|
|
void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
|
|
void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
|
|
void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
|
|
void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
|
|
void sqlite3_str_reset(sqlite3_str*);
|
|
</pre></blockquote>
|
|
<p>
|
|
These interfaces add content to an sqlite3_str object previously obtained
|
|
from <a href="#sqlite3_str_new">sqlite3_str_new()</a>.</p>
|
|
|
|
<p>The <a href="#sqlite3_str_append">sqlite3_str_appendf(X,F,...)</a> and
|
|
<a href="#sqlite3_str_append">sqlite3_str_vappendf(X,F,V)</a> interfaces uses the <a href="printf.html">built-in printf</a>
|
|
functionality of SQLite to append formatted text onto the end of
|
|
<a href="#sqlite3_str">sqlite3_str</a> object X.</p>
|
|
|
|
<p>The <a href="#sqlite3_str_append">sqlite3_str_append(X,S,N)</a> method appends exactly N bytes from string S
|
|
onto the end of the <a href="#sqlite3_str">sqlite3_str</a> object X. N must be non-negative.
|
|
S must contain at least N non-zero bytes of content. To append a
|
|
zero-terminated string in its entirety, use the <a href="#sqlite3_str_append">sqlite3_str_appendall()</a>
|
|
method instead.</p>
|
|
|
|
<p>The <a href="#sqlite3_str_append">sqlite3_str_appendall(X,S)</a> method appends the complete content of
|
|
zero-terminated string S onto the end of <a href="#sqlite3_str">sqlite3_str</a> object X.</p>
|
|
|
|
<p>The <a href="#sqlite3_str_append">sqlite3_str_appendchar(X,N,C)</a> method appends N copies of the
|
|
single-byte character C onto the end of <a href="#sqlite3_str">sqlite3_str</a> object X.
|
|
This method can be used, for example, to add whitespace indentation.</p>
|
|
|
|
<p>The <a href="#sqlite3_str_append">sqlite3_str_reset(X)</a> method resets the string under construction
|
|
inside <a href="#sqlite3_str">sqlite3_str</a> object X back to zero bytes in length.</p>
|
|
|
|
<p>These methods do not return a result code. If an error occurs, that fact
|
|
is recorded in the <a href="#sqlite3_str">sqlite3_str</a> object and can be recovered by a
|
|
subsequent call to <a href="#sqlite3_str_errcode">sqlite3_str_errcode(X)</a>.
|
|
</p><hr><a name="sqlite3_str_errcode"></a>
|
|
<h2>Status Of A Dynamic String</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_str_errcode(sqlite3_str*);
|
|
int sqlite3_str_length(sqlite3_str*);
|
|
char *sqlite3_str_value(sqlite3_str*);
|
|
</pre></blockquote>
|
|
<p>
|
|
These interfaces return the current status of an <a href="#sqlite3_str">sqlite3_str</a> object.</p>
|
|
|
|
<p>If any prior errors have occurred while constructing the dynamic string
|
|
in sqlite3_str X, then the <a href="#sqlite3_str_errcode">sqlite3_str_errcode(X)</a> method will return
|
|
an appropriate error code. The <a href="#sqlite3_str_errcode">sqlite3_str_errcode(X)</a> method returns
|
|
<a href="#SQLITE_ABORT">SQLITE_NOMEM</a> following any out-of-memory error, or
|
|
<a href="#SQLITE_ABORT">SQLITE_TOOBIG</a> if the size of the dynamic string exceeds
|
|
<a href="limits.html#max_length">SQLITE_MAX_LENGTH</a>, or <a href="#SQLITE_ABORT">SQLITE_OK</a> if there have been no errors.</p>
|
|
|
|
<p>The <a href="#sqlite3_str_errcode">sqlite3_str_length(X)</a> method returns the current length, in bytes,
|
|
of the dynamic string under construction in <a href="#sqlite3_str">sqlite3_str</a> object X.
|
|
The length returned by <a href="#sqlite3_str_errcode">sqlite3_str_length(X)</a> does not include the
|
|
zero-termination byte.</p>
|
|
|
|
<p>The <a href="#sqlite3_str_errcode">sqlite3_str_value(X)</a> method returns a pointer to the current
|
|
content of the dynamic string under construction in X. The value
|
|
returned by <a href="#sqlite3_str_errcode">sqlite3_str_value(X)</a> is managed by the sqlite3_str object X
|
|
and might be freed or altered by any subsequent method on the same
|
|
<a href="#sqlite3_str">sqlite3_str</a> object. Applications must not used the pointer returned
|
|
<a href="#sqlite3_str_errcode">sqlite3_str_value(X)</a> after any subsequent method call on the same
|
|
object. Applications may change the content of the string returned
|
|
by <a href="#sqlite3_str_errcode">sqlite3_str_value(X)</a> as long as they do not write into any bytes
|
|
outside the range of 0 to <a href="#sqlite3_str_errcode">sqlite3_str_length(X)</a> and do not read or
|
|
write any byte after any subsequent sqlite3_str method call.
|
|
</p><hr><a name="sqlite3_stricmp"></a>
|
|
<h2>String Comparison</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_stricmp(const char *, const char *);
|
|
int sqlite3_strnicmp(const char *, const char *, int);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_stricmp">sqlite3_stricmp()</a> and <a href="#sqlite3_stricmp">sqlite3_strnicmp()</a> APIs allow applications
|
|
and extensions to compare the contents of two buffers containing UTF-8
|
|
strings in a case-independent fashion, using the same definition of "case
|
|
independence" that SQLite uses internally when comparing identifiers.
|
|
</p><hr><a name="sqlite3_uri_boolean"></a>
|
|
<h2>Obtain Values For URI Parameters</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
|
|
int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
|
|
sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
|
|
const char *sqlite3_uri_key(const char *zFilename, int N);
|
|
</pre></blockquote>
|
|
<p>
|
|
These are utility routines, useful to <a href="vfs.html">custom VFS implementations</a>,
|
|
that check if a database file was a URI that contained a specific query
|
|
parameter, and if so obtains the value of that query parameter.</p>
|
|
|
|
<p>The first parameter to these interfaces (hereafter referred to
|
|
as F) must be one of:
|
|
<ul>
|
|
<li> A database filename pointer created by the SQLite core and
|
|
passed into the xOpen() method of a VFS implemention, or
|
|
<li> A filename obtained from <a href="#sqlite3_db_filename">sqlite3_db_filename()</a>, or
|
|
<li> A new filename constructed using <a href="#sqlite3_create_filename">sqlite3_create_filename()</a>.
|
|
</ul>
|
|
If the F parameter is not one of the above, then the behavior is
|
|
undefined and probably undesirable. Older versions of SQLite were
|
|
more tolerant of invalid F parameters than newer versions.</p>
|
|
|
|
<p>If F is a suitable filename (as described in the previous paragraph)
|
|
and if P is the name of the query parameter, then
|
|
sqlite3_uri_parameter(F,P) returns the value of the P
|
|
parameter if it exists or a NULL pointer if P does not appear as a
|
|
query parameter on F. If P is a query parameter of F and it
|
|
has no explicit value, then sqlite3_uri_parameter(F,P) returns
|
|
a pointer to an empty string.</p>
|
|
|
|
<p>The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
|
|
parameter and returns true (1) or false (0) according to the value
|
|
of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
|
|
value of query parameter P is one of "yes", "true", or "on" in any
|
|
case or if the value begins with a non-zero number. The
|
|
sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
|
|
query parameter P is one of "no", "false", or "off" in any case or
|
|
if the value begins with a numeric zero. If P is not a query
|
|
parameter on F or if the value of P does not match any of the
|
|
above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).</p>
|
|
|
|
<p>The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
|
|
64-bit signed integer and returns that integer, or D if P does not
|
|
exist. If the value of P is something other than an integer, then
|
|
zero is returned.</p>
|
|
|
|
<p>The sqlite3_uri_key(F,N) returns a pointer to the name (not
|
|
the value) of the N-th query parameter for filename F, or a NULL
|
|
pointer if N is less than zero or greater than the number of query
|
|
parameters minus 1. The N value is zero-based so N should be 0 to obtain
|
|
the name of the first query parameter, 1 for the second parameter, and
|
|
so forth.</p>
|
|
|
|
<p>If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
|
|
sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and
|
|
is not a database file pathname pointer that the SQLite core passed
|
|
into the xOpen VFS method, then the behavior of this routine is undefined
|
|
and probably undesirable.</p>
|
|
|
|
<p>Beginning with SQLite <a href="releaselog/3_31_0.html">version 3.31.0</a> (2020-01-22) the input F
|
|
parameter can also be the name of a rollback journal file or WAL file
|
|
in addition to the main database file. Prior to version 3.31.0, these
|
|
routines would only work if F was the name of the main database file.
|
|
When the F parameter is the name of the rollback journal or WAL file,
|
|
it has access to all the same query parameters as were found on the
|
|
main database file.</p>
|
|
|
|
<p>See the <a href="uri.html">URI filename</a> documentation for additional information.
|
|
</p><hr><a name="sqlite3_value_blob"></a>
|
|
<h2>Obtaining SQL Values</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const void *sqlite3_value_blob(sqlite3_value*);
|
|
double sqlite3_value_double(sqlite3_value*);
|
|
int sqlite3_value_int(sqlite3_value*);
|
|
sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
|
|
void *sqlite3_value_pointer(sqlite3_value*, const char*);
|
|
const unsigned char *sqlite3_value_text(sqlite3_value*);
|
|
const void *sqlite3_value_text16(sqlite3_value*);
|
|
const void *sqlite3_value_text16le(sqlite3_value*);
|
|
const void *sqlite3_value_text16be(sqlite3_value*);
|
|
int sqlite3_value_bytes(sqlite3_value*);
|
|
int sqlite3_value_bytes16(sqlite3_value*);
|
|
int sqlite3_value_type(sqlite3_value*);
|
|
int sqlite3_value_numeric_type(sqlite3_value*);
|
|
int sqlite3_value_nochange(sqlite3_value*);
|
|
int sqlite3_value_frombind(sqlite3_value*);
|
|
</pre></blockquote>
|
|
<p>
|
|
<b>Summary:</b>
|
|
<blockquote><table border=0 cellpadding=0 cellspacing=0>
|
|
<tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value
|
|
<tr><td><b>sqlite3_value_double</b><td>→<td>REAL value
|
|
<tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value
|
|
<tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value
|
|
<tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value
|
|
<tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value
|
|
<tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in
|
|
the native byteorder
|
|
<tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value
|
|
<tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value
|
|
<tr><td> <td> <td>
|
|
<tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB
|
|
or a UTF-8 TEXT in bytes
|
|
<tr><td><b>sqlite3_value_bytes16 </b>
|
|
<td>→ <td>Size of UTF-16
|
|
TEXT in bytes
|
|
<tr><td><b>sqlite3_value_type</b><td>→<td>Default
|
|
datatype of the value
|
|
<tr><td><b>sqlite3_value_numeric_type </b>
|
|
<td>→ <td>Best numeric datatype of the value
|
|
<tr><td><b>sqlite3_value_nochange </b>
|
|
<td>→ <td>True if the column is unchanged in an UPDATE
|
|
against a virtual table.
|
|
<tr><td><b>sqlite3_value_frombind </b>
|
|
<td>→ <td>True if value originated from a <a href="lang_expr.html#varparam">bound parameter</a>
|
|
</table></blockquote></p>
|
|
|
|
<p><b>Details:</b></p>
|
|
|
|
<p>These routines extract type, size, and content information from
|
|
<a href="#sqlite3_value">protected sqlite3_value</a> objects. Protected sqlite3_value objects
|
|
are used to pass parameter information into the functions that
|
|
implement <a href="appfunc.html">application-defined SQL functions</a> and <a href="vtab.html">virtual tables</a>.</p>
|
|
|
|
<p>These routines work only with <a href="#sqlite3_value">protected sqlite3_value</a> objects.
|
|
Any attempt to use these routines on an <a href="#sqlite3_value">unprotected sqlite3_value</a>
|
|
is not threadsafe.</p>
|
|
|
|
<p>These routines work just like the corresponding <a href="#sqlite3_column_blob">column access functions</a>
|
|
except that these routines take a single <a href="#sqlite3_value">protected sqlite3_value</a> object
|
|
pointer instead of a <a href="#sqlite3_stmt">sqlite3_stmt*</a> pointer and an integer column number.</p>
|
|
|
|
<p>The sqlite3_value_text16() interface extracts a UTF-16 string
|
|
in the native byte-order of the host machine. The
|
|
sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
|
|
extract UTF-16 strings as big-endian and little-endian respectively.</p>
|
|
|
|
<p>If <a href="#sqlite3_value">sqlite3_value</a> object V was initialized
|
|
using <a href="#sqlite3_bind_blob">sqlite3_bind_pointer(S,I,P,X,D)</a> or <a href="#sqlite3_result_blob">sqlite3_result_pointer(C,P,X,D)</a>
|
|
and if X and Y are strings that compare equal according to strcmp(X,Y),
|
|
then sqlite3_value_pointer(V,Y) will return the pointer P. Otherwise,
|
|
sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
|
|
routine is part of the <a href="bindptr.html">pointer passing interface</a> added for SQLite 3.20.0.</p>
|
|
|
|
<p>The sqlite3_value_type(V) interface returns the
|
|
<a href="#SQLITE_BLOB">datatype code</a> for the initial datatype of the
|
|
<a href="#sqlite3_value">sqlite3_value</a> object V. The returned value is one of <a href="#SQLITE_BLOB">SQLITE_INTEGER</a>,
|
|
<a href="#SQLITE_BLOB">SQLITE_FLOAT</a>, <a href="#SQLITE_BLOB">SQLITE_TEXT</a>, <a href="#SQLITE_BLOB">SQLITE_BLOB</a>, or <a href="#SQLITE_BLOB">SQLITE_NULL</a>.
|
|
Other interfaces might change the datatype for an sqlite3_value object.
|
|
For example, if the datatype is initially SQLITE_INTEGER and
|
|
sqlite3_value_text(V) is called to extract a text value for that
|
|
integer, then subsequent calls to sqlite3_value_type(V) might return
|
|
SQLITE_TEXT. Whether or not a persistent internal datatype conversion
|
|
occurs is undefined and may change from one release of SQLite to the next.</p>
|
|
|
|
<p>The sqlite3_value_numeric_type() interface attempts to apply
|
|
numeric affinity to the value. This means that an attempt is
|
|
made to convert the value to an integer or floating point. If
|
|
such a conversion is possible without loss of information (in other
|
|
words, if the value is a string that looks like a number)
|
|
then the conversion is performed. Otherwise no conversion occurs.
|
|
The <a href="#SQLITE_BLOB">datatype</a> after conversion is returned.</p>
|
|
|
|
<p>Within the <a href="vtab.html#xupdate">xUpdate</a> method of a <a href="vtab.html">virtual table</a>, the
|
|
sqlite3_value_nochange(X) interface returns true if and only if
|
|
the column corresponding to X is unchanged by the UPDATE operation
|
|
that the xUpdate method call was invoked to implement and if
|
|
and the prior <a href="vtab.html#xcolumn">xColumn</a> method call that was invoked to extracted
|
|
the value for that column returned without setting a result (probably
|
|
because it queried <a href="#sqlite3_vtab_nochange">sqlite3_vtab_nochange()</a> and found that the column
|
|
was unchanging). Within an <a href="vtab.html#xupdate">xUpdate</a> method, any value for which
|
|
sqlite3_value_nochange(X) is true will in all other respects appear
|
|
to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other
|
|
than within an <a href="vtab.html#xupdate">xUpdate</a> method call for an UPDATE statement, then
|
|
the return value is arbitrary and meaningless.</p>
|
|
|
|
<p>The sqlite3_value_frombind(X) interface returns non-zero if the
|
|
value X originated from one of the <a href="#sqlite3_bind_blob">sqlite3_bind()</a>
|
|
interfaces. If X comes from an SQL literal value, or a table column,
|
|
or an expression, then sqlite3_value_frombind(X) returns zero.</p>
|
|
|
|
<p>Please pay particular attention to the fact that the pointer returned
|
|
from <a href="#sqlite3_value_blob">sqlite3_value_blob()</a>, <a href="#sqlite3_value_blob">sqlite3_value_text()</a>, or
|
|
<a href="#sqlite3_value_blob">sqlite3_value_text16()</a> can be invalidated by a subsequent call to
|
|
<a href="#sqlite3_value_blob">sqlite3_value_bytes()</a>, <a href="#sqlite3_value_blob">sqlite3_value_bytes16()</a>, <a href="#sqlite3_value_blob">sqlite3_value_text()</a>,
|
|
or <a href="#sqlite3_value_blob">sqlite3_value_text16()</a>.</p>
|
|
|
|
<p>These routines must be called from the same thread as
|
|
the SQL function that supplied the <a href="#sqlite3_value">sqlite3_value*</a> parameters.</p>
|
|
|
|
<p>As long as the input parameter is correct, these routines can only
|
|
fail if an out-of-memory error occurs during a format conversion.
|
|
Only the following subset of interfaces are subject to out-of-memory
|
|
errors:</p>
|
|
|
|
<p><ul>
|
|
<li> sqlite3_value_blob()
|
|
<li> sqlite3_value_text()
|
|
<li> sqlite3_value_text16()
|
|
<li> sqlite3_value_text16le()
|
|
<li> sqlite3_value_text16be()
|
|
<li> sqlite3_value_bytes()
|
|
<li> sqlite3_value_bytes16()
|
|
</ul></p>
|
|
|
|
<p>If an out-of-memory error occurs, then the return value from these
|
|
routines is the same as if the column had contained an SQL NULL value.
|
|
Valid SQL NULL returns can be distinguished from out-of-memory errors
|
|
by invoking the <a href="#sqlite3_errcode">sqlite3_errcode()</a> immediately after the suspect
|
|
return value is obtained and before any
|
|
other SQLite interface is called on the same <a href="#sqlite3">database connection</a>.
|
|
</p><hr><a name="sqlite3_value_dup"></a>
|
|
<h2>Copy And Free SQL Values</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
|
|
void sqlite3_value_free(sqlite3_value*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_value_dup(V) interface makes a copy of the <a href="#sqlite3_value">sqlite3_value</a>
|
|
object D and returns a pointer to that copy. The <a href="#sqlite3_value">sqlite3_value</a> returned
|
|
is a <a href="#sqlite3_value">protected sqlite3_value</a> object even if the input is not.
|
|
The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
|
|
memory allocation fails.</p>
|
|
|
|
<p>The sqlite3_value_free(V) interface frees an <a href="#sqlite3_value">sqlite3_value</a> object
|
|
previously obtained from <a href="#sqlite3_value_dup">sqlite3_value_dup()</a>. If V is a NULL pointer
|
|
then sqlite3_value_free(V) is a harmless no-op.
|
|
</p><hr><a name="sqlite3_vfs_find"></a>
|
|
<h2>Virtual File System Objects</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
|
|
int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
|
|
int sqlite3_vfs_unregister(sqlite3_vfs*);
|
|
</pre></blockquote>
|
|
<p>
|
|
A virtual filesystem (VFS) is an <a href="#sqlite3_vfs">sqlite3_vfs</a> object
|
|
that SQLite uses to interact
|
|
with the underlying operating system. Most SQLite builds come with a
|
|
single default VFS that is appropriate for the host computer.
|
|
New VFSes can be registered and existing VFSes can be unregistered.
|
|
The following interfaces are provided.</p>
|
|
|
|
<p>The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
|
|
Names are case sensitive.
|
|
Names are zero-terminated UTF-8 strings.
|
|
If there is no match, a NULL pointer is returned.
|
|
If zVfsName is NULL then the default VFS is returned.</p>
|
|
|
|
<p>New VFSes are registered with sqlite3_vfs_register().
|
|
Each new VFS becomes the default VFS if the makeDflt flag is set.
|
|
The same VFS can be registered multiple times without injury.
|
|
To make an existing VFS into the default VFS, register it again
|
|
with the makeDflt flag set. If two different VFSes with the
|
|
same name are registered, the behavior is undefined. If a
|
|
VFS is registered with a name that is NULL or an empty string,
|
|
then the behavior is undefined.</p>
|
|
|
|
<p>Unregister a VFS with the sqlite3_vfs_unregister() interface.
|
|
If the default VFS is unregistered, another VFS is chosen as
|
|
the default. The choice for the new VFS is arbitrary.
|
|
</p><hr><a name="sqlite3_win32_set_directory"></a>
|
|
<h2>Win32 Specific Interface</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_win32_set_directory(
|
|
unsigned long type, /* Identifier for directory being set or reset */
|
|
void *zValue /* New value for directory being set or reset */
|
|
);
|
|
int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
|
|
int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
|
|
</pre></blockquote>
|
|
<p>
|
|
These interfaces are available only on Windows. The
|
|
<a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory</a> interface is used to set the value associated
|
|
with the <a href="#sqlite3_temp_directory">sqlite3_temp_directory</a> or <a href="#sqlite3_data_directory">sqlite3_data_directory</a> variable, to
|
|
zValue, depending on the value of the type parameter. The zValue parameter
|
|
should be NULL to cause the previous value to be freed via <a href="#sqlite3_free">sqlite3_free</a>;
|
|
a non-NULL value will be copied into memory obtained from <a href="#sqlite3_free">sqlite3_malloc</a>
|
|
prior to being used. The <a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory</a> interface returns
|
|
<a href="#SQLITE_ABORT">SQLITE_OK</a> to indicate success, <a href="#SQLITE_ABORT">SQLITE_ERROR</a> if the type is unsupported,
|
|
or <a href="#SQLITE_ABORT">SQLITE_NOMEM</a> if memory could not be allocated. The value of the
|
|
<a href="#sqlite3_data_directory">sqlite3_data_directory</a> variable is intended to act as a replacement for
|
|
the current directory on the sub-platforms of Win32 where that concept is
|
|
not present, e.g. WinRT and UWP. The <a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory8</a> and
|
|
<a href="#sqlite3_win32_set_directory">sqlite3_win32_set_directory16</a> interfaces behave exactly the same as the
|
|
sqlite3_win32_set_directory interface except the string parameter must be
|
|
UTF-8 or UTF-16, respectively.
|
|
</p><hr><a name="sqlite3_bind_blob"></a>
|
|
<h2>Binding Values To Prepared Statements</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
|
|
int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
|
|
void(*)(void*));
|
|
int sqlite3_bind_double(sqlite3_stmt*, int, double);
|
|
int sqlite3_bind_int(sqlite3_stmt*, int, int);
|
|
int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
|
|
int sqlite3_bind_null(sqlite3_stmt*, int);
|
|
int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
|
|
int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
|
|
int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
|
|
void(*)(void*), unsigned char encoding);
|
|
int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
|
|
int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
|
|
int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
|
|
int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
|
|
</pre></blockquote>
|
|
<p>
|
|
In the SQL statement text input to <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and its variants,
|
|
literals may be replaced by a <a href="lang_expr.html#varparam">parameter</a> that matches one of following
|
|
templates:</p>
|
|
|
|
<p><ul>
|
|
<li> ?
|
|
<li> ?NNN
|
|
<li> :VVV
|
|
<li> @VVV
|
|
<li> $VVV
|
|
</ul></p>
|
|
|
|
<p>In the templates above, NNN represents an integer literal,
|
|
and VVV represents an alphanumeric identifier. The values of these
|
|
parameters (also called "host parameter names" or "SQL parameters")
|
|
can be set using the sqlite3_bind_*() routines defined here.</p>
|
|
|
|
<p>The first argument to the sqlite3_bind_*() routines is always
|
|
a pointer to the <a href="#sqlite3_stmt">sqlite3_stmt</a> object returned from
|
|
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or its variants.</p>
|
|
|
|
<p>The second argument is the index of the SQL parameter to be set.
|
|
The leftmost SQL parameter has an index of 1. When the same named
|
|
SQL parameter is used more than once, second and subsequent
|
|
occurrences have the same index as the first occurrence.
|
|
The index for named parameters can be looked up using the
|
|
<a href="#sqlite3_bind_parameter_index">sqlite3_bind_parameter_index()</a> API if desired. The index
|
|
for "?NNN" parameters is the value of NNN.
|
|
The NNN value must be between 1 and the <a href="#sqlite3_limit">sqlite3_limit()</a>
|
|
parameter <a href="#sqlitelimitvariablenumber">SQLITE_LIMIT_VARIABLE_NUMBER</a> (default value: 32766).</p>
|
|
|
|
<p>The third argument is the value to bind to the parameter.
|
|
If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
|
|
or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
|
|
is ignored and the end result is the same as sqlite3_bind_null().
|
|
If the third parameter to sqlite3_bind_text() is not NULL, then
|
|
it should be a pointer to well-formed UTF8 text.
|
|
If the third parameter to sqlite3_bind_text16() is not NULL, then
|
|
it should be a pointer to well-formed UTF16 text.
|
|
If the third parameter to sqlite3_bind_text64() is not NULL, then
|
|
it should be a pointer to a well-formed unicode string that is
|
|
either UTF8 if the sixth parameter is SQLITE_UTF8, or UTF16
|
|
otherwise.</p>
|
|
|
|
<p><a name="byteorderdeterminationrules"></a>
|
|
The byte-order of
|
|
UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
|
|
found in first character, which is removed, or in the absence of a BOM
|
|
the byte order is the native byte order of the host
|
|
machine for sqlite3_bind_text16() or the byte order specified in
|
|
the 6th parameter for sqlite3_bind_text64().
|
|
If UTF16 input text contains invalid unicode
|
|
characters, then SQLite might change those invalid characters
|
|
into the unicode replacement character: U+FFFD.</p>
|
|
|
|
<p>In those routines that have a fourth argument, its value is the
|
|
number of bytes in the parameter. To be clear: the value is the
|
|
number of <u>bytes</u> in the value, not the number of characters.
|
|
If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
|
|
is negative, then the length of the string is
|
|
the number of bytes up to the first zero terminator.
|
|
If the fourth parameter to sqlite3_bind_blob() is negative, then
|
|
the behavior is undefined.
|
|
If a non-negative fourth parameter is provided to sqlite3_bind_text()
|
|
or sqlite3_bind_text16() or sqlite3_bind_text64() then
|
|
that parameter must be the byte offset
|
|
where the NUL terminator would occur assuming the string were NUL
|
|
terminated. If any NUL characters occurs at byte offsets less than
|
|
the value of the fourth parameter then the resulting string value will
|
|
contain embedded NULs. The result of expressions involving strings
|
|
with embedded NULs is undefined.</p>
|
|
|
|
<p>The fifth argument to the BLOB and string binding interfaces
|
|
is a destructor used to dispose of the BLOB or
|
|
string after SQLite has finished with it. The destructor is called
|
|
to dispose of the BLOB or string even if the call to the bind API fails,
|
|
except the destructor is not called if the third parameter is a NULL
|
|
pointer or the fourth parameter is negative.
|
|
If the fifth argument is
|
|
the special value <a href="#SQLITE_STATIC">SQLITE_STATIC</a>, then SQLite assumes that the
|
|
information is in static, unmanaged space and does not need to be freed.
|
|
If the fifth argument has the value <a href="#SQLITE_STATIC">SQLITE_TRANSIENT</a>, then
|
|
SQLite makes its own private copy of the data immediately, before
|
|
the sqlite3_bind_*() routine returns.</p>
|
|
|
|
<p>The sixth argument to sqlite3_bind_text64() must be one of
|
|
<a href="#SQLITE_ANY">SQLITE_UTF8</a>, <a href="#SQLITE_ANY">SQLITE_UTF16</a>, <a href="#SQLITE_ANY">SQLITE_UTF16BE</a>, or <a href="#SQLITE_ANY">SQLITE_UTF16LE</a>
|
|
to specify the encoding of the text in the third parameter. If
|
|
the sixth argument to sqlite3_bind_text64() is not one of the
|
|
allowed values shown above, or if the text encoding is different
|
|
from the encoding specified by the sixth parameter, then the behavior
|
|
is undefined.</p>
|
|
|
|
<p>The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
|
|
is filled with zeroes. A zeroblob uses a fixed amount of memory
|
|
(just an integer to hold its size) while it is being processed.
|
|
Zeroblobs are intended to serve as placeholders for BLOBs whose
|
|
content is later written using
|
|
<a href="#sqlite3_blob_open">incremental BLOB I/O</a> routines.
|
|
A negative value for the zeroblob results in a zero-length BLOB.</p>
|
|
|
|
<p>The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
|
|
<a href="#sqlite3_stmt">prepared statement</a> S to have an SQL value of NULL, but to also be
|
|
associated with the pointer P of type T. D is either a NULL pointer or
|
|
a pointer to a destructor function for P. SQLite will invoke the
|
|
destructor D with a single argument of P when it is finished using
|
|
P. The T parameter should be a static string, preferably a string
|
|
literal. The sqlite3_bind_pointer() routine is part of the
|
|
<a href="bindptr.html">pointer passing interface</a> added for SQLite 3.20.0.</p>
|
|
|
|
<p>If any of the sqlite3_bind_*() routines are called with a NULL pointer
|
|
for the <a href="#sqlite3_stmt">prepared statement</a> or with a prepared statement for which
|
|
<a href="#sqlite3_step">sqlite3_step()</a> has been called more recently than <a href="#sqlite3_reset">sqlite3_reset()</a>,
|
|
then the call will return <a href="#SQLITE_ABORT">SQLITE_MISUSE</a>. If any sqlite3_bind_()
|
|
routine is passed a <a href="#sqlite3_stmt">prepared statement</a> that has been finalized, the
|
|
result is undefined and probably harmful.</p>
|
|
|
|
<p>Bindings are not cleared by the <a href="#sqlite3_reset">sqlite3_reset()</a> routine.
|
|
Unbound parameters are interpreted as NULL.</p>
|
|
|
|
<p>The sqlite3_bind_* routines return <a href="#SQLITE_ABORT">SQLITE_OK</a> on success or an
|
|
<a href="rescode.html">error code</a> if anything goes wrong.
|
|
<a href="#SQLITE_ABORT">SQLITE_TOOBIG</a> might be returned if the size of a string or BLOB
|
|
exceeds limits imposed by <a href="#sqlite3_limit">sqlite3_limit</a>(<a href="#sqlitelimitlength">SQLITE_LIMIT_LENGTH</a>) or
|
|
<a href="limits.html#max_length">SQLITE_MAX_LENGTH</a>.
|
|
<a href="#SQLITE_ABORT">SQLITE_RANGE</a> is returned if the parameter
|
|
index is out of range. <a href="#SQLITE_ABORT">SQLITE_NOMEM</a> is returned if malloc() fails.</p>
|
|
|
|
<p>See also: <a href="#sqlite3_bind_parameter_count">sqlite3_bind_parameter_count()</a>,
|
|
<a href="#sqlite3_bind_parameter_name">sqlite3_bind_parameter_name()</a>, and <a href="#sqlite3_bind_parameter_index">sqlite3_bind_parameter_index()</a>.
|
|
</p><hr><a name="sqlite3_prepare"></a>
|
|
<h2>Compiling An SQL Statement</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_prepare(
|
|
sqlite3 *db, /* Database handle */
|
|
const char *zSql, /* SQL statement, UTF-8 encoded */
|
|
int nByte, /* Maximum length of zSql in bytes. */
|
|
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
|
|
const char **pzTail /* OUT: Pointer to unused portion of zSql */
|
|
);
|
|
int sqlite3_prepare_v2(
|
|
sqlite3 *db, /* Database handle */
|
|
const char *zSql, /* SQL statement, UTF-8 encoded */
|
|
int nByte, /* Maximum length of zSql in bytes. */
|
|
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
|
|
const char **pzTail /* OUT: Pointer to unused portion of zSql */
|
|
);
|
|
int sqlite3_prepare_v3(
|
|
sqlite3 *db, /* Database handle */
|
|
const char *zSql, /* SQL statement, UTF-8 encoded */
|
|
int nByte, /* Maximum length of zSql in bytes. */
|
|
unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
|
|
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
|
|
const char **pzTail /* OUT: Pointer to unused portion of zSql */
|
|
);
|
|
int sqlite3_prepare16(
|
|
sqlite3 *db, /* Database handle */
|
|
const void *zSql, /* SQL statement, UTF-16 encoded */
|
|
int nByte, /* Maximum length of zSql in bytes. */
|
|
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
|
|
const void **pzTail /* OUT: Pointer to unused portion of zSql */
|
|
);
|
|
int sqlite3_prepare16_v2(
|
|
sqlite3 *db, /* Database handle */
|
|
const void *zSql, /* SQL statement, UTF-16 encoded */
|
|
int nByte, /* Maximum length of zSql in bytes. */
|
|
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
|
|
const void **pzTail /* OUT: Pointer to unused portion of zSql */
|
|
);
|
|
int sqlite3_prepare16_v3(
|
|
sqlite3 *db, /* Database handle */
|
|
const void *zSql, /* SQL statement, UTF-16 encoded */
|
|
int nByte, /* Maximum length of zSql in bytes. */
|
|
unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
|
|
sqlite3_stmt **ppStmt, /* OUT: Statement handle */
|
|
const void **pzTail /* OUT: Pointer to unused portion of zSql */
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
To execute an SQL statement, it must first be compiled into a byte-code
|
|
program using one of these routines. Or, in other words, these routines
|
|
are constructors for the <a href="#sqlite3_stmt">prepared statement</a> object.</p>
|
|
|
|
<p>The preferred routine to use is <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>. The
|
|
<a href="#sqlite3_prepare">sqlite3_prepare()</a> interface is legacy and should be avoided.
|
|
<a href="#sqlite3_prepare">sqlite3_prepare_v3()</a> has an extra "prepFlags" option that is used
|
|
for special purposes.</p>
|
|
|
|
<p>The use of the UTF-8 interfaces is preferred, as SQLite currently
|
|
does all parsing using UTF-8. The UTF-16 interfaces are provided
|
|
as a convenience. The UTF-16 interfaces work by converting the
|
|
input text into UTF-8, then invoking the corresponding UTF-8 interface.</p>
|
|
|
|
<p>The first argument, "db", is a <a href="#sqlite3">database connection</a> obtained from a
|
|
prior successful call to <a href="#sqlite3_open">sqlite3_open()</a>, <a href="#sqlite3_open">sqlite3_open_v2()</a> or
|
|
<a href="#sqlite3_open">sqlite3_open16()</a>. The database connection must not have been closed.</p>
|
|
|
|
<p>The second argument, "zSql", is the statement to be compiled, encoded
|
|
as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(),
|
|
and sqlite3_prepare_v3()
|
|
interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
|
|
and sqlite3_prepare16_v3() use UTF-16.</p>
|
|
|
|
<p>If the nByte argument is negative, then zSql is read up to the
|
|
first zero terminator. If nByte is positive, then it is the
|
|
number of bytes read from zSql. If nByte is zero, then no prepared
|
|
statement is generated.
|
|
If the caller knows that the supplied string is nul-terminated, then
|
|
there is a small performance advantage to passing an nByte parameter that
|
|
is the number of bytes in the input string <i>including</i>
|
|
the nul-terminator.</p>
|
|
|
|
<p>If pzTail is not NULL then *pzTail is made to point to the first byte
|
|
past the end of the first SQL statement in zSql. These routines only
|
|
compile the first statement in zSql, so *pzTail is left pointing to
|
|
what remains uncompiled.</p>
|
|
|
|
<p>*ppStmt is left pointing to a compiled <a href="#sqlite3_stmt">prepared statement</a> that can be
|
|
executed using <a href="#sqlite3_step">sqlite3_step()</a>. If there is an error, *ppStmt is set
|
|
to NULL. If the input text contains no SQL (if the input is an empty
|
|
string or a comment) then *ppStmt is set to NULL.
|
|
The calling procedure is responsible for deleting the compiled
|
|
SQL statement using <a href="#sqlite3_finalize">sqlite3_finalize()</a> after it has finished with it.
|
|
ppStmt may not be NULL.</p>
|
|
|
|
<p>On success, the sqlite3_prepare() family of routines return <a href="#SQLITE_ABORT">SQLITE_OK</a>;
|
|
otherwise an <a href="rescode.html">error code</a> is returned.</p>
|
|
|
|
<p>The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
|
|
and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
|
|
The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
|
|
are retained for backwards compatibility, but their use is discouraged.
|
|
In the "vX" interfaces, the prepared statement
|
|
that is returned (the <a href="#sqlite3_stmt">sqlite3_stmt</a> object) contains a copy of the
|
|
original SQL text. This causes the <a href="#sqlite3_step">sqlite3_step()</a> interface to
|
|
behave differently in three ways:</p>
|
|
|
|
<p><ol>
|
|
<li>
|
|
If the database schema changes, instead of returning <a href="#SQLITE_ABORT">SQLITE_SCHEMA</a> as it
|
|
always used to do, <a href="#sqlite3_step">sqlite3_step()</a> will automatically recompile the SQL
|
|
statement and try to run it again. As many as <a href="compile.html#max_schema_retry">SQLITE_MAX_SCHEMA_RETRY</a>
|
|
retries will occur before sqlite3_step() gives up and returns an error.
|
|
</li></p>
|
|
|
|
<p><li>
|
|
When an error occurs, <a href="#sqlite3_step">sqlite3_step()</a> will return one of the detailed
|
|
<a href="rescode.html">error codes</a> or <a href="rescode.html#extrc">extended error codes</a>. The legacy behavior was that
|
|
<a href="#sqlite3_step">sqlite3_step()</a> would only return a generic <a href="#SQLITE_ABORT">SQLITE_ERROR</a> result code
|
|
and the application would have to make a second call to <a href="#sqlite3_reset">sqlite3_reset()</a>
|
|
in order to find the underlying cause of the problem. With the "v2" prepare
|
|
interfaces, the underlying reason for the error is returned immediately.
|
|
</li></p>
|
|
|
|
<p><li>
|
|
If the specific value bound to a <a href="lang_expr.html#varparam">host parameter</a> in the
|
|
WHERE clause might influence the choice of query plan for a statement,
|
|
then the statement will be automatically recompiled, as if there had been
|
|
a schema change, on the first <a href="#sqlite3_step">sqlite3_step()</a> call following any change
|
|
to the <a href="#sqlite3_bind_blob">bindings</a> of that <a href="lang_expr.html#varparam">parameter</a>.
|
|
The specific value of a WHERE-clause <a href="lang_expr.html#varparam">parameter</a> might influence the
|
|
choice of query plan if the parameter is the left-hand side of a <a href="lang_expr.html#like">LIKE</a>
|
|
or <a href="lang_expr.html#glob">GLOB</a> operator or if the parameter is compared to an indexed column
|
|
and the <a href="compile.html#enable_stat4">SQLITE_ENABLE_STAT4</a> compile-time option is enabled.
|
|
</li>
|
|
</ol></p>
|
|
|
|
<p><p>sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
|
|
the extra prepFlags parameter, which is a bit array consisting of zero or
|
|
more of the <a href="#sqlitepreparepersistent">SQLITE_PREPARE_*</a> flags. The
|
|
sqlite3_prepare_v2() interface works exactly the same as
|
|
sqlite3_prepare_v3() with a zero prepFlags parameter.
|
|
</p><hr><a name="sqlite3_set_authorizer"></a>
|
|
<h2>Compile-Time Authorization Callbacks</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_set_authorizer(
|
|
sqlite3*,
|
|
int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
|
|
void *pUserData
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
This routine registers an authorizer callback with a particular
|
|
<a href="#sqlite3">database connection</a>, supplied in the first argument.
|
|
The authorizer callback is invoked as SQL statements are being compiled
|
|
by <a href="#sqlite3_prepare">sqlite3_prepare()</a> or its variants <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a>,
|
|
<a href="#sqlite3_prepare">sqlite3_prepare_v3()</a>, <a href="#sqlite3_prepare">sqlite3_prepare16()</a>, <a href="#sqlite3_prepare">sqlite3_prepare16_v2()</a>,
|
|
and <a href="#sqlite3_prepare">sqlite3_prepare16_v3()</a>. At various
|
|
points during the compilation process, as logic is being created
|
|
to perform various actions, the authorizer callback is invoked to
|
|
see if those actions are allowed. The authorizer callback should
|
|
return <a href="#SQLITE_ABORT">SQLITE_OK</a> to allow the action, <a href="#SQLITE_DENY">SQLITE_IGNORE</a> to disallow the
|
|
specific action but allow the SQL statement to continue to be
|
|
compiled, or <a href="#SQLITE_DENY">SQLITE_DENY</a> to cause the entire SQL statement to be
|
|
rejected with an error. If the authorizer callback returns
|
|
any value other than <a href="#SQLITE_DENY">SQLITE_IGNORE</a>, <a href="#SQLITE_ABORT">SQLITE_OK</a>, or <a href="#SQLITE_DENY">SQLITE_DENY</a>
|
|
then the <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or equivalent call that triggered
|
|
the authorizer will fail with an error message.</p>
|
|
|
|
<p>When the callback returns <a href="#SQLITE_ABORT">SQLITE_OK</a>, that means the operation
|
|
requested is ok. When the callback returns <a href="#SQLITE_DENY">SQLITE_DENY</a>, the
|
|
<a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or equivalent call that triggered the
|
|
authorizer will fail with an error message explaining that
|
|
access is denied.</p>
|
|
|
|
<p>The first parameter to the authorizer callback is a copy of the third
|
|
parameter to the sqlite3_set_authorizer() interface. The second parameter
|
|
to the callback is an integer <a href="#SQLITE_ALTER_TABLE">action code</a> that specifies
|
|
the particular action to be authorized. The third through sixth parameters
|
|
to the callback are either NULL pointers or zero-terminated strings
|
|
that contain additional details about the action to be authorized.
|
|
Applications must always be prepared to encounter a NULL pointer in any
|
|
of the third through the sixth parameters of the authorization callback.</p>
|
|
|
|
<p>If the action code is <a href="#SQLITE_ALTER_TABLE">SQLITE_READ</a>
|
|
and the callback returns <a href="#SQLITE_DENY">SQLITE_IGNORE</a> then the
|
|
<a href="#sqlite3_stmt">prepared statement</a> statement is constructed to substitute
|
|
a NULL value in place of the table column that would have
|
|
been read if <a href="#SQLITE_ABORT">SQLITE_OK</a> had been returned. The <a href="#SQLITE_DENY">SQLITE_IGNORE</a>
|
|
return can be used to deny an untrusted user access to individual
|
|
columns of a table.
|
|
When a table is referenced by a <a href="lang_select.html">SELECT</a> but no column values are
|
|
extracted from that table (for example in a query like
|
|
"SELECT count(*) FROM tab") then the <a href="#SQLITE_ALTER_TABLE">SQLITE_READ</a> authorizer callback
|
|
is invoked once for that table with a column name that is an empty string.
|
|
If the action code is <a href="#SQLITE_ALTER_TABLE">SQLITE_DELETE</a> and the callback returns
|
|
<a href="#SQLITE_DENY">SQLITE_IGNORE</a> then the <a href="lang_delete.html">DELETE</a> operation proceeds but the
|
|
<a href="lang_delete.html#truncateopt">truncate optimization</a> is disabled and all rows are deleted individually.</p>
|
|
|
|
<p>An authorizer is used when <a href="#sqlite3_prepare">preparing</a>
|
|
SQL statements from an untrusted source, to ensure that the SQL statements
|
|
do not try to access data they are not allowed to see, or that they do not
|
|
try to execute malicious statements that damage the database. For
|
|
example, an application may allow a user to enter arbitrary
|
|
SQL queries for evaluation by a database. But the application does
|
|
not want the user to be able to make arbitrary changes to the
|
|
database. An authorizer could then be put in place while the
|
|
user-entered SQL is being <a href="#sqlite3_prepare">prepared</a> that
|
|
disallows everything except <a href="lang_select.html">SELECT</a> statements.</p>
|
|
|
|
<p>Applications that need to process SQL from untrusted sources
|
|
might also consider lowering resource limits using <a href="#sqlite3_limit">sqlite3_limit()</a>
|
|
and limiting database size using the <a href="pragma.html#pragma_max_page_count">max_page_count</a> <a href="pragma.html#syntax">PRAGMA</a>
|
|
in addition to using an authorizer.</p>
|
|
|
|
<p>Only a single authorizer can be in place on a database connection
|
|
at a time. Each call to sqlite3_set_authorizer overrides the
|
|
previous call. Disable the authorizer by installing a NULL callback.
|
|
The authorizer is disabled by default.</p>
|
|
|
|
<p>The authorizer callback must not do anything that will modify
|
|
the database connection that invoked the authorizer callback.
|
|
Note that <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> and <a href="#sqlite3_step">sqlite3_step()</a> both modify their
|
|
database connections for the meaning of "modify" in this paragraph.</p>
|
|
|
|
<p>When <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> is used to prepare a statement, the
|
|
statement might be re-prepared during <a href="#sqlite3_step">sqlite3_step()</a> due to a
|
|
schema change. Hence, the application should ensure that the
|
|
correct authorizer callback remains in place during the <a href="#sqlite3_step">sqlite3_step()</a>.</p>
|
|
|
|
<p>Note that the authorizer callback is invoked only during
|
|
<a href="#sqlite3_prepare">sqlite3_prepare()</a> or its variants. Authorization is not
|
|
performed during statement evaluation in <a href="#sqlite3_step">sqlite3_step()</a>, unless
|
|
as stated in the previous paragraph, sqlite3_step() invokes
|
|
sqlite3_prepare_v2() to reprepare a statement after a schema change.
|
|
</p><hr><a name="sqlite3_get_autocommit"></a>
|
|
<h2>Test For Auto-Commit Mode</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_get_autocommit(sqlite3*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_get_autocommit() interface returns non-zero or
|
|
zero if the given database connection is or is not in autocommit mode,
|
|
respectively. Autocommit mode is on by default.
|
|
Autocommit mode is disabled by a <a href="lang_transaction.html">BEGIN</a> statement.
|
|
Autocommit mode is re-enabled by a <a href="lang_transaction.html">COMMIT</a> or <a href="lang_transaction.html">ROLLBACK</a>.</p>
|
|
|
|
<p>If certain kinds of errors occur on a statement within a multi-statement
|
|
transaction (errors including <a href="#SQLITE_ABORT">SQLITE_FULL</a>, <a href="#SQLITE_ABORT">SQLITE_IOERR</a>,
|
|
<a href="#SQLITE_ABORT">SQLITE_NOMEM</a>, <a href="#SQLITE_ABORT">SQLITE_BUSY</a>, and <a href="#SQLITE_ABORT">SQLITE_INTERRUPT</a>) then the
|
|
transaction might be rolled back automatically. The only way to
|
|
find out whether SQLite automatically rolled back the transaction after
|
|
an error is to use this function.</p>
|
|
|
|
<p>If another thread changes the autocommit status of the database
|
|
connection while this routine is running, then the return value
|
|
is undefined.
|
|
</p><hr><a name="sqlite3_busy_handler"></a>
|
|
<h2>Register A Callback To Handle SQLITE_BUSY Errors</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The sqlite3_busy_handler(D,X,P) routine sets a callback function X
|
|
that might be invoked with argument P whenever
|
|
an attempt is made to access a database table associated with
|
|
<a href="#sqlite3">database connection</a> D when another thread
|
|
or process has the table locked.
|
|
The sqlite3_busy_handler() interface is used to implement
|
|
<a href="#sqlite3_busy_timeout">sqlite3_busy_timeout()</a> and <a href="pragma.html#pragma_busy_timeout">PRAGMA busy_timeout</a>.</p>
|
|
|
|
<p>If the busy callback is NULL, then <a href="#SQLITE_ABORT">SQLITE_BUSY</a>
|
|
is returned immediately upon encountering the lock. If the busy callback
|
|
is not NULL, then the callback might be invoked with two arguments.</p>
|
|
|
|
<p>The first argument to the busy handler is a copy of the void* pointer which
|
|
is the third argument to sqlite3_busy_handler(). The second argument to
|
|
the busy handler callback is the number of times that the busy handler has
|
|
been invoked previously for the same locking event. If the
|
|
busy callback returns 0, then no additional attempts are made to
|
|
access the database and <a href="#SQLITE_ABORT">SQLITE_BUSY</a> is returned
|
|
to the application.
|
|
If the callback returns non-zero, then another attempt
|
|
is made to access the database and the cycle repeats.</p>
|
|
|
|
<p>The presence of a busy handler does not guarantee that it will be invoked
|
|
when there is lock contention. If SQLite determines that invoking the busy
|
|
handler could result in a deadlock, it will go ahead and return <a href="#SQLITE_ABORT">SQLITE_BUSY</a>
|
|
to the application instead of invoking the
|
|
busy handler.
|
|
Consider a scenario where one process is holding a read lock that
|
|
it is trying to promote to a reserved lock and
|
|
a second process is holding a reserved lock that it is trying
|
|
to promote to an exclusive lock. The first process cannot proceed
|
|
because it is blocked by the second and the second process cannot
|
|
proceed because it is blocked by the first. If both processes
|
|
invoke the busy handlers, neither will make any progress. Therefore,
|
|
SQLite returns <a href="#SQLITE_ABORT">SQLITE_BUSY</a> for the first process, hoping that this
|
|
will induce the first process to release its read lock and allow
|
|
the second process to proceed.</p>
|
|
|
|
<p>The default busy callback is NULL.</p>
|
|
|
|
<p>There can only be a single busy handler defined for each
|
|
<a href="#sqlite3">database connection</a>. Setting a new busy handler clears any
|
|
previously set handler. Note that calling <a href="#sqlite3_busy_timeout">sqlite3_busy_timeout()</a>
|
|
or evaluating <a href="pragma.html#pragma_busy_timeout">PRAGMA busy_timeout=N</a> will change the
|
|
busy handler and thus clear any previously set busy handler.</p>
|
|
|
|
<p>The busy callback should not take any actions which modify the
|
|
database connection that invoked the busy handler. In other words,
|
|
the busy handler is not reentrant. Any such actions
|
|
result in undefined behavior.</p>
|
|
|
|
<p>A busy handler must not close the database connection
|
|
or <a href="#sqlite3_stmt">prepared statement</a> that invoked the busy handler.
|
|
</p><hr><a name="sqlite3_column_blob"></a>
|
|
<h2>Result Values From A Query</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
|
|
double sqlite3_column_double(sqlite3_stmt*, int iCol);
|
|
int sqlite3_column_int(sqlite3_stmt*, int iCol);
|
|
sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
|
|
const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
|
|
const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
|
|
sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
|
|
int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
|
|
int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
|
|
int sqlite3_column_type(sqlite3_stmt*, int iCol);
|
|
</pre></blockquote>
|
|
<p>
|
|
<b>Summary:</b>
|
|
<blockquote><table border=0 cellpadding=0 cellspacing=0>
|
|
<tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result
|
|
<tr><td><b>sqlite3_column_double</b><td>→<td>REAL result
|
|
<tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result
|
|
<tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result
|
|
<tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result
|
|
<tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result
|
|
<tr><td><b>sqlite3_column_value</b><td>→<td>The result as an
|
|
<a href="#sqlite3_value">unprotected sqlite3_value</a> object.
|
|
<tr><td> <td> <td>
|
|
<tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB
|
|
or a UTF-8 TEXT result in bytes
|
|
<tr><td><b>sqlite3_column_bytes16 </b>
|
|
<td>→ <td>Size of UTF-16
|
|
TEXT in bytes
|
|
<tr><td><b>sqlite3_column_type</b><td>→<td>Default
|
|
datatype of the result
|
|
</table></blockquote></p>
|
|
|
|
<p><b>Details:</b></p>
|
|
|
|
<p>These routines return information about a single column of the current
|
|
result row of a query. In every case the first argument is a pointer
|
|
to the <a href="#sqlite3_stmt">prepared statement</a> that is being evaluated (the <a href="#sqlite3_stmt">sqlite3_stmt*</a>
|
|
that was returned from <a href="#sqlite3_prepare">sqlite3_prepare_v2()</a> or one of its variants)
|
|
and the second argument is the index of the column for which information
|
|
should be returned. The leftmost column of the result set has the index 0.
|
|
The number of columns in the result can be determined using
|
|
<a href="#sqlite3_column_count">sqlite3_column_count()</a>.</p>
|
|
|
|
<p>If the SQL statement does not currently point to a valid row, or if the
|
|
column index is out of range, the result is undefined.
|
|
These routines may only be called when the most recent call to
|
|
<a href="#sqlite3_step">sqlite3_step()</a> has returned <a href="#SQLITE_ABORT">SQLITE_ROW</a> and neither
|
|
<a href="#sqlite3_reset">sqlite3_reset()</a> nor <a href="#sqlite3_finalize">sqlite3_finalize()</a> have been called subsequently.
|
|
If any of these routines are called after <a href="#sqlite3_reset">sqlite3_reset()</a> or
|
|
<a href="#sqlite3_finalize">sqlite3_finalize()</a> or after <a href="#sqlite3_step">sqlite3_step()</a> has returned
|
|
something other than <a href="#SQLITE_ABORT">SQLITE_ROW</a>, the results are undefined.
|
|
If <a href="#sqlite3_step">sqlite3_step()</a> or <a href="#sqlite3_reset">sqlite3_reset()</a> or <a href="#sqlite3_finalize">sqlite3_finalize()</a>
|
|
are called from a different thread while any of these routines
|
|
are pending, then the results are undefined.</p>
|
|
|
|
<p>The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
|
|
each return the value of a result column in a specific data format. If
|
|
the result column is not initially in the requested format (for example,
|
|
if the query returns an integer but the sqlite3_column_text() interface
|
|
is used to extract the value) then an automatic type conversion is performed.</p>
|
|
|
|
<p>The sqlite3_column_type() routine returns the
|
|
<a href="#SQLITE_BLOB">datatype code</a> for the initial data type
|
|
of the result column. The returned value is one of <a href="#SQLITE_BLOB">SQLITE_INTEGER</a>,
|
|
<a href="#SQLITE_BLOB">SQLITE_FLOAT</a>, <a href="#SQLITE_BLOB">SQLITE_TEXT</a>, <a href="#SQLITE_BLOB">SQLITE_BLOB</a>, or <a href="#SQLITE_BLOB">SQLITE_NULL</a>.
|
|
The return value of sqlite3_column_type() can be used to decide which
|
|
of the first six interface should be used to extract the column value.
|
|
The value returned by sqlite3_column_type() is only meaningful if no
|
|
automatic type conversions have occurred for the value in question.
|
|
After a type conversion, the result of calling sqlite3_column_type()
|
|
is undefined, though harmless. Future
|
|
versions of SQLite may change the behavior of sqlite3_column_type()
|
|
following a type conversion.</p>
|
|
|
|
<p>If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
|
|
or sqlite3_column_bytes16() interfaces can be used to determine the size
|
|
of that BLOB or string.</p>
|
|
|
|
<p>If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
|
|
routine returns the number of bytes in that BLOB or string.
|
|
If the result is a UTF-16 string, then sqlite3_column_bytes() converts
|
|
the string to UTF-8 and then returns the number of bytes.
|
|
If the result is a numeric value then sqlite3_column_bytes() uses
|
|
<a href="#sqlite3_mprintf">sqlite3_snprintf()</a> to convert that value to a UTF-8 string and returns
|
|
the number of bytes in that string.
|
|
If the result is NULL, then sqlite3_column_bytes() returns zero.</p>
|
|
|
|
<p>If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
|
|
routine returns the number of bytes in that BLOB or string.
|
|
If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
|
|
the string to UTF-16 and then returns the number of bytes.
|
|
If the result is a numeric value then sqlite3_column_bytes16() uses
|
|
<a href="#sqlite3_mprintf">sqlite3_snprintf()</a> to convert that value to a UTF-16 string and returns
|
|
the number of bytes in that string.
|
|
If the result is NULL, then sqlite3_column_bytes16() returns zero.</p>
|
|
|
|
<p>The values returned by <a href="#sqlite3_column_blob">sqlite3_column_bytes()</a> and
|
|
<a href="#sqlite3_column_blob">sqlite3_column_bytes16()</a> do not include the zero terminators at the end
|
|
of the string. For clarity: the values returned by
|
|
<a href="#sqlite3_column_blob">sqlite3_column_bytes()</a> and <a href="#sqlite3_column_blob">sqlite3_column_bytes16()</a> are the number of
|
|
bytes in the string, not the number of characters.</p>
|
|
|
|
<p>Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
|
|
even empty strings, are always zero-terminated. The return
|
|
value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.</p>
|
|
|
|
<p><b>Warning:</b> The object returned by <a href="#sqlite3_column_blob">sqlite3_column_value()</a> is an
|
|
<a href="#sqlite3_value">unprotected sqlite3_value</a> object. In a multithreaded environment,
|
|
an unprotected sqlite3_value object may only be used safely with
|
|
<a href="#sqlite3_bind_blob">sqlite3_bind_value()</a> and <a href="#sqlite3_result_blob">sqlite3_result_value()</a>.
|
|
If the <a href="#sqlite3_value">unprotected sqlite3_value</a> object returned by
|
|
<a href="#sqlite3_column_blob">sqlite3_column_value()</a> is used in any other way, including calls
|
|
to routines like <a href="#sqlite3_value_blob">sqlite3_value_int()</a>, <a href="#sqlite3_value_blob">sqlite3_value_text()</a>,
|
|
or <a href="#sqlite3_value_blob">sqlite3_value_bytes()</a>, the behavior is not threadsafe.
|
|
Hence, the sqlite3_column_value() interface
|
|
is normally only useful within the implementation of
|
|
<a href="appfunc.html">application-defined SQL functions</a> or <a href="vtab.html">virtual tables</a>, not within
|
|
top-level application code.</p>
|
|
|
|
<p>The these routines may attempt to convert the datatype of the result.
|
|
For example, if the internal representation is FLOAT and a text result
|
|
is requested, <a href="#sqlite3_mprintf">sqlite3_snprintf()</a> is used internally to perform the
|
|
conversion automatically. The following table details the conversions
|
|
that are applied:</p>
|
|
|
|
<p><blockquote>
|
|
<table border="1">
|
|
<tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion</p>
|
|
|
|
<p><tr><td> NULL <td> INTEGER <td> Result is 0
|
|
<tr><td> NULL <td> FLOAT <td> Result is 0.0
|
|
<tr><td> NULL <td> TEXT <td> Result is a NULL pointer
|
|
<tr><td> NULL <td> BLOB <td> Result is a NULL pointer
|
|
<tr><td> INTEGER <td> FLOAT <td> Convert from integer to float
|
|
<tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer
|
|
<tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT
|
|
<tr><td> FLOAT <td> INTEGER <td> <a href="lang_expr.html#castexpr">CAST</a> to INTEGER
|
|
<tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float
|
|
<tr><td> FLOAT <td> BLOB <td> <a href="lang_expr.html#castexpr">CAST</a> to BLOB
|
|
<tr><td> TEXT <td> INTEGER <td> <a href="lang_expr.html#castexpr">CAST</a> to INTEGER
|
|
<tr><td> TEXT <td> FLOAT <td> <a href="lang_expr.html#castexpr">CAST</a> to REAL
|
|
<tr><td> TEXT <td> BLOB <td> No change
|
|
<tr><td> BLOB <td> INTEGER <td> <a href="lang_expr.html#castexpr">CAST</a> to INTEGER
|
|
<tr><td> BLOB <td> FLOAT <td> <a href="lang_expr.html#castexpr">CAST</a> to REAL
|
|
<tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed
|
|
</table>
|
|
</blockquote></p>
|
|
|
|
<p>Note that when type conversions occur, pointers returned by prior
|
|
calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
|
|
sqlite3_column_text16() may be invalidated.
|
|
Type conversions and pointer invalidations might occur
|
|
in the following cases:</p>
|
|
|
|
<p><ul>
|
|
<li> The initial content is a BLOB and sqlite3_column_text() or
|
|
sqlite3_column_text16() is called. A zero-terminator might
|
|
need to be added to the string.</li>
|
|
<li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
|
|
sqlite3_column_text16() is called. The content must be converted
|
|
to UTF-16.</li>
|
|
<li> The initial content is UTF-16 text and sqlite3_column_bytes() or
|
|
sqlite3_column_text() is called. The content must be converted
|
|
to UTF-8.</li>
|
|
</ul></p>
|
|
|
|
<p>Conversions between UTF-16be and UTF-16le are always done in place and do
|
|
not invalidate a prior pointer, though of course the content of the buffer
|
|
that the prior pointer references will have been modified. Other kinds
|
|
of conversion are done in place when it is possible, but sometimes they
|
|
are not possible and in those cases prior pointers are invalidated.</p>
|
|
|
|
<p>The safest policy is to invoke these routines
|
|
in one of the following ways:</p>
|
|
|
|
<p><ul>
|
|
<li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
|
|
<li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
|
|
<li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
|
|
</ul></p>
|
|
|
|
<p>In other words, you should call sqlite3_column_text(),
|
|
sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
|
|
into the desired format, then invoke sqlite3_column_bytes() or
|
|
sqlite3_column_bytes16() to find the size of the result. Do not mix calls
|
|
to sqlite3_column_text() or sqlite3_column_blob() with calls to
|
|
sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
|
|
with calls to sqlite3_column_bytes().</p>
|
|
|
|
<p>The pointers returned are valid until a type conversion occurs as
|
|
described above, or until <a href="#sqlite3_step">sqlite3_step()</a> or <a href="#sqlite3_reset">sqlite3_reset()</a> or
|
|
<a href="#sqlite3_finalize">sqlite3_finalize()</a> is called. The memory space used to hold strings
|
|
and BLOBs is freed automatically. Do not pass the pointers returned
|
|
from <a href="#sqlite3_column_blob">sqlite3_column_blob()</a>, <a href="#sqlite3_column_blob">sqlite3_column_text()</a>, etc. into
|
|
<a href="#sqlite3_free">sqlite3_free()</a>.</p>
|
|
|
|
<p>As long as the input parameters are correct, these routines will only
|
|
fail if an out-of-memory error occurs during a format conversion.
|
|
Only the following subset of interfaces are subject to out-of-memory
|
|
errors:</p>
|
|
|
|
<p><ul>
|
|
<li> sqlite3_column_blob()
|
|
<li> sqlite3_column_text()
|
|
<li> sqlite3_column_text16()
|
|
<li> sqlite3_column_bytes()
|
|
<li> sqlite3_column_bytes16()
|
|
</ul></p>
|
|
|
|
<p>If an out-of-memory error occurs, then the return value from these
|
|
routines is the same as if the column had contained an SQL NULL value.
|
|
Valid SQL NULL returns can be distinguished from out-of-memory errors
|
|
by invoking the <a href="#sqlite3_errcode">sqlite3_errcode()</a> immediately after the suspect
|
|
return value is obtained and before any
|
|
other SQLite interface is called on the same <a href="#sqlite3">database connection</a>.
|
|
</p><hr><a name="sqlite3_file_control"></a>
|
|
<h2>Low-Level Control Of Database Files</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
|
|
</pre></blockquote>
|
|
<p>
|
|
The <a href="#sqlite3_file_control">sqlite3_file_control()</a> interface makes a direct call to the
|
|
xFileControl method for the <a href="#sqlite3_io_methods">sqlite3_io_methods</a> object associated
|
|
with a particular database identified by the second argument. The
|
|
name of the database is "main" for the main database or "temp" for the
|
|
TEMP database, or the name that appears after the AS keyword for
|
|
databases that are added using the <a href="lang_attach.html">ATTACH</a> SQL command.
|
|
A NULL pointer can be used in place of "main" to refer to the
|
|
main database file.
|
|
The third and fourth parameters to this routine
|
|
are passed directly through to the second and third parameters of
|
|
the xFileControl method. The return value of the xFileControl
|
|
method becomes the return value of this routine.</p>
|
|
|
|
<p>A few opcodes for <a href="#sqlite3_file_control">sqlite3_file_control()</a> are handled directly
|
|
by the SQLite core and never invoke the
|
|
sqlite3_io_methods.xFileControl method.
|
|
The <a href="#sqlitefcntlfilepointer">SQLITE_FCNTL_FILE_POINTER</a> value for the op parameter causes
|
|
a pointer to the underlying <a href="#sqlite3_file">sqlite3_file</a> object to be written into
|
|
the space pointed to by the 4th parameter. The
|
|
<a href="#sqlitefcntljournalpointer">SQLITE_FCNTL_JOURNAL_POINTER</a> works similarly except that it returns
|
|
the <a href="#sqlite3_file">sqlite3_file</a> object associated with the journal file instead of
|
|
the main database. The <a href="#sqlitefcntlvfspointer">SQLITE_FCNTL_VFS_POINTER</a> opcode returns
|
|
a pointer to the underlying <a href="#sqlite3_vfs">sqlite3_vfs</a> object for the file.
|
|
The <a href="#sqlitefcntldataversion">SQLITE_FCNTL_DATA_VERSION</a> returns the data version counter
|
|
from the pager.</p>
|
|
|
|
<p>If the second parameter (zDbName) does not match the name of any
|
|
open database file, then SQLITE_ERROR is returned. This error
|
|
code is not remembered and will not be recalled by <a href="#sqlite3_errcode">sqlite3_errcode()</a>
|
|
or <a href="#sqlite3_errcode">sqlite3_errmsg()</a>. The underlying xFileControl method might
|
|
also return SQLITE_ERROR. There is no way to distinguish between
|
|
an incorrect zDbName and an SQLITE_ERROR return from the underlying
|
|
xFileControl method.</p>
|
|
|
|
<p>See also: <a href="#SQLITE_FCNTL_BEGIN_ATOMIC_WRITE">file control opcodes</a>
|
|
</p><hr><a name="sqlite3_create_function"></a>
|
|
<h2>Create Or Redefine SQL Functions</h2>
|
|
</div>
|
|
<blockquote><pre>
|
|
int sqlite3_create_function(
|
|
sqlite3 *db,
|
|
const char *zFunctionName,
|
|
int nArg,
|
|
int eTextRep,
|
|
void *pApp,
|
|
void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
|
|
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
|
|
void (*xFinal)(sqlite3_context*)
|
|
);
|
|
int sqlite3_create_function16(
|
|
sqlite3 *db,
|
|
const void *zFunctionName,
|
|
int nArg,
|
|
int eTextRep,
|
|
void *pApp,
|
|
void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
|
|
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
|
|
void (*xFinal)(sqlite3_context*)
|
|
);
|
|
int sqlite3_create_function_v2(
|
|
sqlite3 *db,
|
|
const char *zFunctionName,
|
|
int nArg,
|
|
int eTextRep,
|
|
void *pApp,
|
|
void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
|
|
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
|
|
void (*xFinal)(sqlite3_context*),
|
|
void(*xDestroy)(void*)
|
|
);
|
|
int sqlite3_create_window_function(
|
|
sqlite3 *db,
|
|
const char *zFunctionName,
|
|
int nArg,
|
|
int eTextRep,
|
|
void *pApp,
|
|
void (*xStep)(sqlite3_context*,int,sqlite3_value**),
|
|
void (*xFinal)(sqlite3_context*),
|
|
void (*xValue)(sqlite3_context*),
|
|
void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
|
|
void(*xDestroy)(void*)
|
|
);
|
|
</pre></blockquote>
|
|
<p>
|
|
These functions (collectively known as "function creation routines")
|
|
are used to add SQL functions or aggregates or to redefine the behavior
|
|
of existing SQL functions or aggregates. The only differences between
|
|
the three "sqlite3_create_function*" routines are the text encoding
|
|
expected for the second parameter (the name of the function being
|
|
created) and the presence or absence of a destructor callback for
|
|
the application data pointer. Function sqlite3_create_window_function()
|
|
is similar, but allows the user to supply the extra callback functions
|
|
needed by <a href="windowfunctions.html#aggwinfunc">aggregate window functions</a>.</p>
|
|
|
|
<p>The first parameter is the <a href="#sqlite3">database connection</a> to which the SQL
|
|
function is to be added. If an application uses more than one database
|
|
connection then application-defined SQL functions must be added
|
|
to each database connection separately.</p>
|
|
|
|
<p>The second parameter is the name of the SQL function to be created or
|
|
redefined. The length of the name is limited to 255 bytes in a UTF-8
|
|
representation, exclusive of the zero-terminator. Note that the name
|
|
length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
|
|
Any attempt to create a function with a longer name
|
|
will result in <a href="#SQLITE_ABORT">SQLITE_MISUSE</a> being returned.</p>
|
|
|
|
<p>The third parameter (nArg)
|
|
is the number of arguments that the SQL function or
|
|
aggregate takes. If this parameter is -1, then the SQL function or
|
|
aggregate may take any number of arguments between 0 and the limit
|
|
set by <a href="#sqlite3_limit">sqlite3_limit</a>(<a href="#sqlitelimitfunctionarg">SQLITE_LIMIT_FUNCTION_ARG</a>). If the third
|
|
parameter is less than -1 or greater than 127 then the behavior is
|
|
undefined.</p>
|
|
|
|
<p>The fourth parameter, eTextRep, specifies what
|
|
<a href="#SQLITE_ANY">text encoding</a> this SQL function prefers for
|
|
its parameters. The application should set this parameter to
|
|
<a href="#SQLITE_ANY">SQLITE_UTF16LE</a> if the function implementation invokes
|
|
<a href="#sqlite3_value_blob">sqlite3_value_text16le()</a> on an input, or <a href="#SQLITE_ANY">SQLITE_UTF16BE</a> if the
|
|
implementation invokes <a href="#sqlite3_value_blob">sqlite3_value_text16be()</a> on an input, or
|
|
<a href="#SQLITE_ANY">SQLITE_UTF16</a> if <a href="#sqlite3_value_blob">sqlite3_value_text16()</a> is used, or <a href="#SQLITE_ANY">SQLITE_UTF8</a>
|
|
otherwise. The same SQL function may be registered multiple times using
|
|
different preferred text encodings, with different implementations for
|
|
each encoding.
|
|
When multiple implementations of the same function are available, SQLite
|
|
will pick the one that involves the least amount of data conversion.</p>
|
|
|
|
<p>The fourth parameter may optionally be ORed with <a href="#sqlitedeterministic">SQLITE_DETERMINISTIC</a>
|
|
to signal that the function will always return the same result given
|
|
the same inputs within a single SQL statement. Most SQL functions are
|
|
deterministic. The built-in <a href="lang_corefunc.html#random">random()</a> SQL function is an example of a
|
|
function that is not deterministic. The SQLite query planner is able to
|
|
perform additional optimizations on deterministic functions, so use
|
|
of the <a href="#sqlitedeterministic">SQLITE_DETERMINISTIC</a> flag is recommended where possible.</p>
|
|
|
|
<p>The fourth parameter may also optionally include the <a href="#sqlitedirectonly">SQLITE_DIRECTONLY</a>
|
|
flag, which if present prevents the function from being invoked from
|
|
within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
|
|
index expressions, or the WHERE clause of partial indexes.</p>
|
|
|
|
<p><span style="background-color:#ffff90;">
|
|
For best security, the <a href="#sqlitedirectonly">SQLITE_DIRECTONLY</a> flag is recommended for
|
|
all application-defined SQL functions that do not need to be
|
|
used inside of triggers, view, CHECK constraints, or other elements of
|
|
the database schema. This flags is especially recommended for SQL
|
|
functions that have side effects or reveal internal application state.
|
|
Without this flag, an attacker might be able to modify the schema of
|
|
a database file to include invocations of the function with parameters
|
|
chosen by the attacker, which the application will then execute when
|
|
the database file is opened and read.
|
|
</span></p>
|
|
|
|
<p>The fifth parameter is an arbitrary pointer. The implementation of the
|
|
function can gain access to this pointer using <a href="#sqlite3_user_data">sqlite3_user_data()</a>.</p>
|
|
|
|
<p>The sixth, seventh and eighth parameters passed to the three
|
|
"sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
|
|
pointers to C-language functions that implement the SQL function or
|
|
aggregate. A scalar SQL function requires an implementation of the xFunc
|
|
callback only; NULL pointers must be passed as the xStep and xFinal
|
|
parameters. An aggregate SQL function requires an implementation of xStep
|
|
and xFinal and NULL pointer must be passed for xFunc. To delete an existing
|
|
SQL function or aggregate, pass NULL pointers for all three function
|
|
callbacks.</p>
|
|
|
|
<p>The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
|
|
and xInverse) passed to sqlite3_create_window_function are pointers to
|
|
C-language callbacks that implement the new function. xStep and xFinal
|
|
must both be non-NULL. xValue and xInverse may either both be NULL, in
|
|
which case a regular aggregate function is created, or must both be
|
|
non-NULL, in which case the new function may be used as either an aggregate
|
|
or aggregate window function. More details regarding the implementation
|
|
of aggregate window functions are
|
|
<a href="windowfunctions.html#udfwinfunc">available here</a>.</p>
|
|
|
|
<p>If the final parameter to sqlite3_create_function_v2() or
|
|
sqlite3_create_window_function() is not NULL, then it is destructor for
|
|
the application data pointer. The destructor is invoked when the function
|
|
is deleted, either by being overloaded or when the database connection
|
|
closes. The destructor is also invoked if the call to
|
|
sqlite3_create_function_v2() fails. When the destructor callback is
|
|
invoked, it is passed a single argument which is a copy of the application
|
|
data pointer which was the fifth parameter to sqlite3_create_function_v2().</p>
|
|
|
|
<p>It is permitted to register multiple implementations of the same
|
|
functions with the same name but with either differing numbers of
|
|
arguments or differing preferred text encodings. SQLite will use
|
|
the implementation that most closely matches the way in which the
|
|
SQL function is used. A function implementation with a non-negative
|
|
nArg parameter is a better match than a function implementation with
|
|
a negative nArg. A function where the preferred text encoding
|
|
matches the database encoding is a better
|
|
match than a function where the encoding is different.
|
|
A function where the encoding difference is between UTF16le and UTF16be
|
|
is a closer match than a function where the encoding difference is
|
|
between UTF8 and UTF16.</p>
|
|
|
|
<p>Built-in functions may be overloaded by new application-defined functions.</p>
|
|
|
|
<p>An application-defined function is permitted to call other
|
|
SQLite interfaces. However, such calls must not
|
|
close the database connection nor finalize or reset the prepared
|
|
statement in which the function is running.
|
|
</p><hr>
|
|
|