Alessandro Bonazzi 5c7aa8c1c0 Patch level : 12.0 no-patch
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Aggiunta documentazione di sqlite 3
2020-11-29 00:32:36 +01:00

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<h2>SQLite Release 3.20.1 On 2017-08-24</h2><p><b>Changes in version 3.20.0 (2017-08-01):</b></p>
<p><ol class='lessindent'>
<li value='1'> Update the text of error messages returned by <a href="../c3ref/errcode.html">sqlite3_errmsg()</a> for some
error codes.
<li> Add new <a href="../bindptr.html">pointer passing interfaces</a>.
<li> Backwards-incompatible changes to some extensions in order to take
advantage of the improved security offered by the new
<a href="../bindptr.html">pointer passing interfaces</a>:
<ol type='a'>
<li> <a href="../fts5.html#extending_fts5">Extending FTS5</a> &rarr; requires <a href="../c3ref/bind_blob.html">sqlite3_bind_pointer()</a> to find
the fts5_api pointer.
<li> <a href="../carray.html">carray(PTR,N)</a> &rarr; requires <a href="../c3ref/bind_blob.html">sqlite3_bind_pointer()</a> to set the PTR parameter.
<li> <a href="https://www.sqlite.org/src/file/ext/misc/remember.c">remember(V,PTR)</a>
&rarr; requires <a href="../c3ref/bind_blob.html">sqlite3_bind_pointer()</a> to set the PTR parameter.
</ol>
<li> Added the <a href="../stmt.html">SQLITE_STMT virtual table</a> extension.
<li> Added the <a href="../completion.html">COMPLETION extension</a> - designed to suggest
tab-completions for interactive user interfaces. This is a work in progress.
Expect further enhancements in future releases.
<li> Added the <a href="../unionvtab.html">UNION virtual table</a> extension.
<li> The built-in <a href="../lang_datefunc.html">date and time functions</a> have been enhanced so that they can be
used in <a href="../lang_createtable.html#ckconst">CHECK constraints</a>, in <a href="../expridx.html">indexes on expressions</a>, and in the WHERE clauses
of <a href="../partialindex.html">partial indexes</a>, provided that they do not use the 'now', 'localtime', or
'utc' keywords. <a href="../deterministic.html#dtexception">More information</a>.
<li> Added the <a href="../c3ref/prepare.html">sqlite3_prepare_v3()</a> and <a href="../c3ref/prepare.html">sqlite3_prepare16_v3()</a> interfaces
with the extra "prepFlags" parameters.
<li> Provide the <a href="../c3ref/c_prepare_normalize.html#sqlitepreparepersistent">SQLITE_PREPARE_PERSISTENT</a> flag for <a href="../c3ref/prepare.html">sqlite3_prepare_v3()</a> and
use it to limit <a href="../malloc.html#lookaside">lookaside memory</a> misuse by <a href="../fts3.html">FTS3</a>, <a href="../fts5.html">FTS5</a>, and the
<a href="../rtree.html">R-Tree extension</a>.
<li> Added the <a href="../pragma.html#pragma_secure_delete">PRAGMA secure_delete=FAST</a> command. When secure_delete is
set to FAST, old content is overwritten with zeros as long as that does
not increase the amount of I/O. Deleted content might still persist on
the <a href="../fileformat2.html#freelist">free-page list</a> but will be purged from all b-tree pages.
<li> Enhancements to the <a href="../cli.html">command-line shell</a>:
<ol type='a'>
<li> Add support for tab-completion using the <a href="../completion.html">COMPLETION extension</a>, for
both readline and linenoise.
<li> Add the ".cd" command.
<li> Enhance the "<a href="../cli.html#dschema">.schema</a>" command to show the schema of all attached
databases.
<li> Enhance "<a href="../cli.html#dtables">.tables</a>" so that it shows the schema names for all attached
if the name is anything other than "main".
<li> The "<a href="../cli.html#csv">.import</a>" command ignores an initial UTF-8 BOM.
<li> Added the "--newlines" option to the "<a href="../cli.html#dump">.dump</a>" command to cause U+000a and
U+000d characters to be output literally rather than escaped using the
<a href="../lang_corefunc.html#replace">replace()</a> function.
</ol>
<li> Query planner enhancements:
<ol type='a'>
<li> When generating individual loops for each ORed term of an OR scan,
move any constant WHERE expressions outside of the loop, as is
done for top-level loops.
<li> The query planner examines the values of bound parameters to help
determine if a partial index is usable.
<li> When deciding between two plans with the same estimated cost, bias
the selection toward the one that does not use the sorter.
<li> Evaluate WHERE clause constraints involving correlated subqueries
last, in the hope that they never have be evaluated at all.
<li> Do not use the <a href="../optoverview.html#flattening">flattening optimization</a> for a sub-query on the RHS
of a LEFT JOIN if that subquery reads data from a <a href="../vtab.html">virtual table</a> as
doing so prevents the query planner from creating <a href="../optoverview.html#autoindex">automatic indexes</a>
on the results of the sub-query, which can slow down the query.
</ol>
<li> Add <a href="../c3ref/c_stmtstatus_counter.html#sqlitestmtstatusreprepare">SQLITE_STMTSTATUS_REPREPARE</a>, <a href="../c3ref/c_stmtstatus_counter.html#sqlitestmtstatusrun">SQLITE_STMTSTATUS_RUN</a>,
and <a href="../c3ref/c_stmtstatus_counter.html#sqlitestmtstatusmemused">SQLITE_STMTSTATUS_MEMUSED</a> options for the
<a href="../c3ref/stmt_status.html">sqlite3_stmt_status()</a> interface.
<li> Provide <a href="../pragma.html#pragfunc">PRAGMA functions</a> for
<a href="../pragma.html#pragma_integrity_check">PRAGMA integrity_check</a>, <a href="../pragma.html#pragma_quick_check">PRAGMA quick_check</a>, and
<a href="../pragma.html#pragma_foreign_key_check">PRAGMA foreign_key_check</a>.
<li> Add the -withoutnulls option to the <a href="../tclsqlite.html#eval">TCL interface eval method</a>.
<li> Enhance the <a href="../sqlanalyze.html">sqlite3_analyzer.exe</a> utility program so that it shows
the number of bytes of metadata on btree pages.
<li> The <a href="../c3ref/c_dbconfig_defensive.html#sqlitedbconfigenableqpsg">SQLITE_DBCONFIG_ENABLE_QPSG</a> run-time option and the
<a href="../compile.html#enable_qpsg">SQLITE_ENABLE_QPSG</a> compile-time option enable the
<a href="../queryplanner-ng.html#qpstab">query planner stability guarantee</a>. See also ticket
<a href="https://www.sqlite.org/src/info/892fc34f173e99d8">892fc34f173e99d8</a>
<li> Miscellaneous optimizations result in a 2% reduction in <a href="../cpu.html">CPU cycles used</a>.
<p><b>Bug Fixes:</b>
<li> Fix the behavior of <a href="../c3ref/column_name.html">sqlite3_column_name()</a> for queries that use the
<a href="../optoverview.html#flattening">flattening optimization</a> so that the result is consistent with other
queries that do not use that optimization, and with PostgreSQL, MySQL,
and SQLServer. Ticket <a href="https://sqlite.org/src/info/de3403bf5ae">de3403bf5ae</a>.
<li> Fix the query planner so that it knows not to use <a href="../optoverview.html#autoindex">automatic indexes</a>
on the right table of LEFT JOIN if the WHERE clause uses the <a href="../lang_expr.html#isisnot">IS operator</a>.
Fix for <a href="https://sqlite.org/src/info/ce68383bf6aba">ce68383bf6aba</a>.
<li> Ensure that the query planner knows that any column of a
<a href="../optoverview.html#flattening">flattened</a> LEFT JOIN can be NULL even
if that column is labeled with "NOT NULL". Fix for ticket
<a href="https://sqlite.org/src/info/892fc34f173e99d8">892fc34f173e99d8</a>.
<li> Fix rare false-positives in <a href="../pragma.html#pragma_integrity_check">PRAGMA integrity_check</a> when run on a database connection
with <a href="../lang_attach.html">attached databases</a>. Ticket
<a href="https://sqlite.org/src/info/a4e06e75a9ab61a12">a4e06e75a9ab61a12</a>
<li> Fix a bug (discovered by OSSFuzz) that causes an assertion fault if certain
dodgy CREATE TABLE declarations are used. Ticket
<a href="https://sqlite.org/src/info/bc115541132dad136">bc115541132dad136</a>
</ol>
<p><b>Additional changes in version 3.20.1:</b></p>
<p><ol class='lessindent'>
<li value='24'> Fix a potential memory leak in the new <a href="../c3ref/result_blob.html">sqlite3_result_pointer()</a> interface.
Ticket <a href="https://sqlite.org/src/info/7486aa54b968e9b5">7486aa54b968e9b5</a>.
<p><b>Hashes:</b>
<li>SQLITE_SOURCE_ID: "2017-08-24 16:21:36 8d3a7ea6c5690d6b7c3767558f4f01b511c55463e3f9e64506801fe9b74dce34"
<li>SHA3-256 for sqlite3.c: 93b1a6d69b48dc39697d1d3a1e4c30b55da0bdd2cad0c054462f91081832954a
</ol></p>
<p>A <a href="../changes.html">complete list of SQLite releases</a>
in a single page and a <a href="../chronology.html">chronology</a> are both also available.
A detailed history of every
check-in is available at
<a href="http://www.sqlite.org/src/timeline">
SQLite version control site</a>.</p>