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Aggiunto help query e report git-svn-id: svn://10.65.10.50/trunk@11973 c028cbd2-c16b-5b4b-a496-9718f37d4682
2004-04-14 14:47:59 +00:00
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML><HEAD><TITLE>Query Language Understood By SQLite</TITLE>
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<BODY bgcolor="#ffffff" leftmargin="5">
<H1 align=center>SQL As Understood By SQLite </H1>
<P align=center>(This page was last modified on 2004/01/19 05:09:24 UTC) </P>
<P>The SQLite library understands most of the standard SQL language. But it does
<A href="http://www.hwaci.com/sw/sqlite/omitted.html">omit some features</A>
while at the same time adding a few features of its own. This document attempts
to describe percisely what parts of the SQL language SQLite does and does not
support. A list of <A
href="#keywords">keywords</A> is given
at the end.</P>
<P>In all of the syntax diagrams that follow, literal text is shown in bold
blue. Non-terminal symbols are shown in italic red. Operators that are part of
the syntactic markup itself are shown in black roman.</P>
<P>This document is just an overview of the SQL syntax implemented by SQLite.
Many low-level productions are omitted. For detailed information on the language
that SQLite understands, refer to the source code and the grammar file
"parse.y".</P>
<P>SQLite implements the follow syntax:</P>
<P>
<UL>
<LI><A href="#attach">ATTACH
DATABASE</A>
<LI><A href="#transaction">BEGIN
TRANSACTION</A>
<LI><A href="#comment">comment</A>
<LI><A href="#transaction">COMMIT
TRANSACTION</A>
<LI><A href="#copy">COPY</A>
<LI><A href="#createindex">CREATE
INDEX</A>
<LI><A href="#createtable">CREATE
TABLE</A>
<LI><A href="#createtrigger">CREATE
TRIGGER</A>
<LI><A href="#createview">CREATE
VIEW</A>
<LI><A href="#delete">DELETE</A>
<LI><A href="#detach">DETACH
DATABASE</A>
<LI><A href="#dropindex">DROP
INDEX</A>
<LI><A href="#droptable">DROP
TABLE</A>
<LI><A href="#droptrigger">DROP
TRIGGER</A>
<LI><A href="#dropview">DROP VIEW</A>
<LI><A href="#transaction">END
TRANSACTION</A>
<LI><A href="#explain">EXPLAIN</A>
<LI><A href="#expr">expression</A>
<LI><A href="#insert">INSERT</A>
<LI><A href="#conflict">ON CONFLICT
clause</A>
<LI><A href="#pragma">PRAGMA</A>
<LI><A href="#replace">REPLACE</A>
<LI><A href="#transaction">ROLLBACK
TRANSACTION</A>
<LI><A href="#select">SELECT</A>
<LI><A href="#update">UPDATE</A>
<LI><A href="#vacuum">VACUUM</A>
</LI></UL>
<P></P>
<P>Details on the implementation of each command are provided in the sequel.</P>
<HR>
<A name=attach></A>
<H1>ATTACH DATABASE</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>ATTACH </FONT></B>[<B><FONT
color=#2c2cf0>DATABASE</FONT></B>]<B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>database-filename</FONT></I><B><FONT
color=#2c2cf0> AS </FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The ATTACH DATABASE statement adds a preexisting database file to the current
database connection. If the filename contains punctuation characters it must be
quoted. The names 'main' and 'temp' refer to the main database and the database
used for temporary tables. These cannot be detached. Attached databases are
removed using the <A
href="#detach">DETACH DATABASE</A>
statement.</P>
<P>You can read from and write to an attached database, but you cannot alter the
schema of an attached database. You can only CREATE and DROP in the original
database.</P>
<P>You cannot create a new table with the same name as a table in an attached
database, but you can attach a database which contains tables whose names are
duplicates of tables in the main database. It is also permissible to attach the
same database file multiple times.</P>
<P>Tables in an attached database can be referred to using the syntax
<I>database-name.table-name</I>. If an attached table doesn't have a duplicate
table name in the main database, it doesn't require a database name prefix. When
a database is attached, all of its tables which don't have duplicate names
become the 'default' table of that name. Any tables of that name attached
afterwards require the table prefix. If the 'default' table of a given name is
detached, then the last table of that name attached becomes the new default.</P>
<P>When there are attached databases, transactions are not atomic. Transactions
continue to be atomic within each individual database file. But if your machine
crashes in the middle of a COMMIT where you have updated two or more database
files, some of those files might get the changes where others might not.</P>
<P>There is a compile-time limit of 10 attached database files.</P>
<P>Executing a BEGIN TRANSACTION statement locks all database files, so this
feature cannot (currently) be used to increase concurrancy.</P>
<HR>
<A name=transaction></A>
<H1>BEGIN TRANSACTION</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>BEGIN </FONT></B>[<B><FONT
color=#2c2cf0>TRANSACTION </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT color=#ff3434>name</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0> </FONT></B>[<B><FONT color=#2c2cf0>ON CONFLICT
</FONT></B><I><FONT color=#ff3434>conflict-algorithm</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>END </FONT></B>[<B><FONT
color=#2c2cf0>TRANSACTION </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT color=#ff3434>name</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>COMMIT </FONT></B>[<B><FONT
color=#2c2cf0>TRANSACTION </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT color=#ff3434>name</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>ROLLBACK </FONT></B>[<B><FONT
color=#2c2cf0>TRANSACTION </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT color=#ff3434>name</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>Beginning in version 2.0, SQLite supports transactions with rollback and
atomic commit. See <A
href="#attach">ATTACH</A> for an
exception when there are attached databases.</P>
<P>The optional transaction name is ignored. SQLite currently doesn't allow
nested transactions. Attempting to start a new transaction inside another is an
error.</P>
<P>No changes can be made to the database except within a transaction. Any
command that changes the database (basically, any SQL command other than SELECT)
will automatically start a transaction if one is not already in effect.
Automatically started transactions are committed at the conclusion of the
command. </P>
<P>Transactions can be started manually using the BEGIN command. Such
transactions usually persist until the next COMMIT or ROLLBACK command. But a
transaction will also ROLLBACK if the database is closed or if an error occurs
and the ROLLBACK conflict resolution algorithm is specified. See the documention
on the <A href="#conflict">ON
CONFLICT</A> clause for additional information about the ROLLBACK conflict
resolution algorithm. </P>
<P>The optional ON CONFLICT clause at the end of a BEGIN statement can be used
to changed the default conflict resolution algorithm. The normal default is
ABORT. If an alternative is specified by the ON CONFLICT clause of a BEGIN, then
that alternative is used as the default for all commands within the transaction.
The default algorithm is overridden by ON CONFLICT clauses on individual
constraints within the CREATE TABLE or CREATE INDEX statements and by the OR
clauses on COPY, INSERT, and UPDATE commands. </P>
<HR>
<A name=comment></A>
<H1>comment</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>comment</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>SQL-comment</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>C-comment</FONT></I><B><FONT color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>SQL-comment</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>-- </FONT></B><I><FONT
color=#ff3434>single-line</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>C-comment</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>/<BIG>*</BIG> </FONT></B><I><FONT
color=#ff3434>multiple-lines</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0><BIG>*</BIG>/</FONT></B>]<B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>Comments aren't SQL commands, but can occur in SQL queries. They are treated
as whitespace by the parser. They can begin anywhere whitespace can be found,
including inside expressions that span multiple lines. </P>
<P>SQL comments only extend to the end of the current line.</P>
<P>C comments can span any number of lines. If there is no terminating
delimiter, they extend to the end of the input. This is not treated as an error.
A new SQL statement can begin on a line after a multiline comment ends. C
comments can be embedded anywhere whitespace can occur, including inside
expressions, and in the middle of other SQL statements. C comments do not nest.
SQL comments inside a C comment will be ignored. </P>
<HR>
<A name=copy></A>
<H1>COPY</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>COPY </FONT></B>[<B><FONT color=#2c2cf0> OR
</FONT></B><I><FONT color=#ff3434>conflict-algorithm</FONT></I><B><FONT
color=#2c2cf0> </FONT></B>]<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0> FROM
</FONT></B><I><FONT color=#ff3434>filename</FONT></I><B><FONT
color=#2c2cf0><BR></FONT></B>[<B><FONT color=#2c2cf0> USING DELIMITERS
</FONT></B><I><FONT color=#ff3434>delim</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>]<B><FONT color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The COPY command is an extension used to load large amounts of data into a
table. It is modeled after a similar command found in PostgreSQL. In fact, the
SQLite COPY command is specifically designed to be able to read the output of
the PostgreSQL dump utility <B>pg_dump</B> so that data can be easily
transferred from PostgreSQL into SQLite.</P>
<P>The table-name is the name of an existing table which is to be filled with
data. The filename is a string or identifier that names a file from which data
will be read. The filename can be the <B>STDIN</B> to read data from standard
input.</P>
<P>Each line of the input file is converted into a single record in the table.
Columns are separated by tabs. If a tab occurs as data within a column, then
that tab is preceded by a baskslash "\" character. A baskslash in the data
appears as two backslashes in a row. The optional USING DELIMITERS clause can
specify a delimiter other than tab.</P>
<P>If a column consists of the character "\N", that column is filled with the
value NULL.</P>
<P>The optional conflict-clause allows the specification of an alternative
constraint conflict resolution algorithm to use for this one command. See the
section titled <A href="#conflict">ON
CONFLICT</A> for additional information.</P>
<P>When the input data source is STDIN, the input can be terminated by a line
that contains only a baskslash and a dot: "<FONT
color=#2c2cf0><BIG>\.</BIG></FONT>".</P>
<HR>
<A name=createindex></A>
<H1>CREATE INDEX</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>CREATE </FONT></B>[<B><FONT
color=#2c2cf0>UNIQUE</FONT></B>]<B><FONT color=#2c2cf0> INDEX
</FONT></B><I><FONT color=#ff3434>index-name</FONT></I><B><FONT
color=#2c2cf0> <BR>ON </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0> <BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>column-name</FONT></I><B><FONT
color=#2c2cf0> </FONT></B>[<B><FONT color=#2c2cf0><BIG>,</BIG>
</FONT></B><I><FONT color=#ff3434>column-name</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT color=#2c2cf0>
<BIG>)</BIG><BR></FONT></B>[<B><FONT color=#2c2cf0> ON CONFLICT
</FONT></B><I><FONT color=#ff3434>conflict-algorithm</FONT></I><B><FONT
color=#2c2cf0> </FONT></B>]<B><FONT color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>column-name</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>name</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0> ASC </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> DESC
</FONT></B>]<B><FONT color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The CREATE INDEX command consists of the keywords "CREATE INDEX" followed by
the name of the new index, the keyword "ON", the name of a previously created
table that is to be indexed, and a parenthesized list of names of columns in the
table that are used for the index key. Each column name can be followed by one
of the "ASC" or "DESC" keywords to indicate sort order, but the sort order is
ignored in the current implementation. Sorting is always done in ascending
order.</P>
<P>There are no arbitrary limits on the number of indices that can be attached
to a single table, nor on the number of columns in an index.</P>
<P>If the UNIQUE keyword appears between CREATE and INDEX then duplicate index
entries are not allowed. Any attempt to insert a duplicate entry will result in
an error.</P>
<P>The optional conflict-clause allows the specification of an alternative
default constraint conflict resolution algorithm for this index. This only makes
sense if the UNIQUE keyword is used since otherwise there are not constraints on
the index. The default algorithm is ABORT. If a COPY, INSERT, or UPDATE
statement specifies a particular conflict resolution algorithm, that algorithm
is used in place of the default algorithm specified here. See the section titled
<A href="#conflict">ON CONFLICT</A> for
additional information.</P>
<P>The exact text of each CREATE INDEX statement is stored in the
<B>sqlite_master</B> or <B>sqlite_temp_master</B> table, depending on whether
the table being indexed is temporary. Everytime the database is opened, all
CREATE INDEX statements are read from the <B>sqlite_master</B> table and used to
regenerate SQLite's internal representation of the index layout.</P>
<P>Indexes cannot be added on tables in attached databases. Indexes are removed
with the <A href="#dropindex">DROP
INDEX</A> command.</P>
<HR>
<A name=createtable></A>
<H1>CREATE TABLE</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-command</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>CREATE </FONT></B>[<B><FONT color=#2c2cf0>TEMP
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
TEMPORARY</FONT></B>]<B><FONT color=#2c2cf0> TABLE </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>(</BIG><BR>&nbsp;&nbsp;&nbsp;&nbsp;</FONT></B><I><FONT
color=#ff3434>column-def</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0><BIG>,</BIG> </FONT></B><I><FONT
color=#ff3434>column-def</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT
color=#2c2cf0><BR>&nbsp;&nbsp;&nbsp;&nbsp;</FONT></B>[<B><FONT
color=#2c2cf0><BIG>,</BIG> </FONT></B><I><FONT
color=#ff3434>constraint</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT
color=#2c2cf0><BR><BIG>)</BIG></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-command</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>CREATE </FONT></B>[<B><FONT color=#2c2cf0>TEMP
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
TEMPORARY</FONT></B>]<B><FONT color=#2c2cf0> TABLE </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0> AS
</FONT></B><I><FONT color=#ff3434>select-statement</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>column-def</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>name</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT color=#ff3434>type</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B>[<B><FONT color=#2c2cf0>CONSTRAINT
</FONT></B><I><FONT color=#ff3434>name</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>column-constraint</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT
color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>type</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>typename</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>typename</FONT></I><B><FONT color=#2c2cf0> <BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>number</FONT></I><B><FONT color=#2c2cf0>
<BIG>)</BIG> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>typename</FONT></I><B><FONT color=#2c2cf0> <BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>number</FONT></I><B><FONT color=#2c2cf0>
<BIG>,</BIG> </FONT></B><I><FONT color=#ff3434>number</FONT></I><B><FONT
color=#2c2cf0> <BIG>)</BIG></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>column-constraint</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>NOT NULL </FONT></B>[<B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>conflict-clause</FONT></I><B><FONT
color=#2c2cf0> </FONT></B>]<B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR>PRIMARY KEY
</FONT></B>[<B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>sort-order</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>conflict-clause</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR>UNIQUE </FONT></B>[<B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>conflict-clause</FONT></I><B><FONT
color=#2c2cf0> </FONT></B>]<B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR>CHECK <BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0>
<BIG>)</BIG> </FONT></B>[<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>conflict-clause</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR>DEFAULT </FONT></B><I><FONT
color=#ff3434>value</FONT></I><B><FONT color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>constraint</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>PRIMARY KEY <BIG>(</BIG> </FONT></B><I><FONT
color=#ff3434>column-list</FONT></I><B><FONT color=#2c2cf0> <BIG>)</BIG>
</FONT></B>[<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>conflict-clause</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR>UNIQUE <BIG>(</BIG> </FONT></B><I><FONT
color=#ff3434>column-list</FONT></I><B><FONT color=#2c2cf0> <BIG>)</BIG>
</FONT></B>[<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>conflict-clause</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR>CHECK <BIG>(</BIG> </FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> <BIG>)</BIG>
</FONT></B>[<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>conflict-clause</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>]<B><FONT color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>conflict-clause</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>ON CONFLICT </FONT></B><I><FONT
color=#ff3434>conflict-algorithm</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>A CREATE TABLE statement is basically the keywords "CREATE TABLE" followed by
the name of a new table and a parenthesized list of column definitions and
constraints. The table name can be either an identifier or a string. Tables
names that begin with "<B>sqlite_</B>" are reserved for use by the engine.</P>
<P>Each column definition is the name of the column followed by the datatype for
that column, then one or more optional column constraints. SQLite is <A
href="http://www.hwaci.com/sw/sqlite/datatypes.html">typeless</A>. The datatype
for the column does not restrict what data may be put in that column. All
information is stored as null-terminated strings. The UNIQUE constraint causes
an index to be created on the specified columns. This index must contain unique
keys. The DEFAULT constraint specifies a default value to use when doing an
INSERT. </P>
<P>Specifying a PRIMARY KEY normally just creates a UNIQUE index on the primary
key. However, if primary key is on a single column that has datatype INTEGER,
then that column is used internally as the actual key of the B-Tree for the
table. This means that the column may only hold unique integer values. (Except
for this one case, SQLite ignores the datatype specification of columns and
allows any kind of data to be put in a column regardless of its declared
datatype.) If a table does not have an INTEGER PRIMARY KEY column, then the
B-Tree key will be a automatically generated integer. The B-Tree key for a row
can always be accessed using one of the special names "<B>ROWID</B>",
"<B>OID</B>", or "<B>_ROWID_</B>". This is true regardless of whether or not
there is an INTEGER PRIMARY KEY.</P>
<P>If the "TEMP" or "TEMPORARY" keyword occurs in between "CREATE" and "TABLE"
then the table that is created is only visible to the process that opened the
database and is automatically deleted when the database is closed. Any indices
created on a temporary table are also temporary. Temporary tables and indices
are stored in a separate file distinct from the main database file.</P>
<P>The optional conflict-clause following each constraint allows the
specification of an alternative default constraint conflict resolution algorithm
for that constraint. The default is abort ABORT. Different constraints within
the same table may have different default conflict resolution algorithms. If an
COPY, INSERT, or UPDATE command specifies a different conflict resolution
algorithm, then that algorithm is used in place of the default algorithm
specified in the CREATE TABLE statement. See the section titled <A
href="#conflict">ON CONFLICT</A> for
additional information.</P>
<P>CHECK constraints are ignored in the current implementation. Support for
CHECK constraints may be added in the future. As of version 2.3.0, NOT NULL,
PRIMARY KEY, and UNIQUE constraints all work.</P>
<P>There are no arbitrary limits on the number of columns or on the number of
constraints in a table. The total amount of data in a single row is limited to
about 1 megabytes. (This limit can be increased to 16MB by changing a single
#define in the source code and recompiling.)</P>
<P>The CREATE TABLE AS form defines the table to be the result set of a query.
The names of the table columns are the names of the columns in the result.</P>
<P>The exact text of each CREATE TABLE statement is stored in the
<B>sqlite_master</B> table. Everytime the database is opened, all CREATE TABLE
statements are read from the <B>sqlite_master</B> table and used to regenerate
SQLite's internal representation of the table layout. If the original command
was a CREATE TABLE AS then then an equivalent CREATE TABLE statement is
synthesized and store in <B>sqlite_master</B> in place of the original command.
The text of CREATE TEMPORARY TABLE statements are stored in the
<B>sqlite_temp_master</B> table. </P>
<P>Tables are removed using the <A
href="#droptable">DROP TABLE</A>
statement. Non-temporary tables in an attached database cannot be dropped.</P>
<HR>
<A name=createtrigger></A>
<H1>CREATE TRIGGER</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>CREATE </FONT></B>[<B><FONT color=#2c2cf0>TEMP
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
TEMPORARY</FONT></B>]<B><FONT color=#2c2cf0> TRIGGER </FONT></B><I><FONT
color=#ff3434>trigger-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0> BEFORE </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0> AFTER </FONT></B>]<B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>database-event</FONT></I><B><FONT color=#2c2cf0> ON
</FONT></B>[<B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>trigger-action</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>CREATE </FONT></B>[<B><FONT color=#2c2cf0>TEMP
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
TEMPORARY</FONT></B>]<B><FONT color=#2c2cf0> TRIGGER </FONT></B><I><FONT
color=#ff3434>trigger-name</FONT></I><B><FONT color=#2c2cf0> INSTEAD
OF<BR></FONT></B><I><FONT color=#ff3434>database-event</FONT></I><B><FONT
color=#2c2cf0> ON </FONT></B>[<B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>view-name</FONT></I><B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>trigger-action</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>database-event</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>DELETE </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0> <BR>INSERT </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
<BR>UPDATE </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> <BR>UPDATE OF
</FONT></B><I><FONT color=#ff3434>column-list</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>trigger-action</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B>[<B><FONT color=#2c2cf0> FOR EACH
ROW </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> FOR EACH STATEMENT
</FONT></B>]<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT color=#2c2cf0>
WHEN </FONT></B><I><FONT color=#ff3434>expression</FONT></I><B><FONT
color=#2c2cf0> </FONT></B>]<B><FONT color=#2c2cf0> <BR>BEGIN
<BR>&nbsp;&nbsp;&nbsp;&nbsp;</FONT></B><I><FONT
color=#ff3434>trigger-step</FONT></I><B><FONT color=#2c2cf0> ;
</FONT></B>[<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>trigger-step</FONT></I><B><FONT color=#2c2cf0> ;
</FONT></B>]<B><FONT color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT
color=#2c2cf0><BR>END</FONT></B></TD></TR></TBODY></TABLE>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>trigger-step</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>update-statement</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>insert-statement</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> <BR></FONT></B><I><FONT
color=#ff3434>delete-statement</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>select-statement</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The CREATE TRIGGER statement is used to add triggers to the database schema.
Triggers are database operations (the <I>trigger-action</I>) that are
automatically performed when a specified database event (the
<I>database-event</I>) occurs. </P>
<P>A trigger may be specified to fire whenever a DELETE, INSERT or UPDATE of a
particular database table occurs, or whenever an UPDATE of one or more specified
columns of a table are updated.</P>
<P>At this time SQLite supports only FOR EACH ROW triggers, not FOR EACH
STATEMENT triggers. Hence explicitly specifying FOR EACH ROW is optional. FOR
EACH ROW implies that the SQL statements specified as <I>trigger-steps</I> may
be executed (depending on the WHEN clause) for each database row being inserted,
updated or deleted by the statement causing the trigger to fire.</P>
<P>Both the WHEN clause and the <I>trigger-steps</I> may access elements of the
row being inserted, deleted or updated using references of the form
"NEW.<I>column-name</I>" and "OLD.<I>column-name</I>", where <I>column-name</I>
is the name of a column from the table that the trigger is associated with. OLD
and NEW references may only be used in triggers on <I>trigger-event</I>s for
which they are relevant, as follows:</P>
<TABLE cellPadding=10 border=0>
<TBODY>
<TR>
<TD vAlign=top align=right width=120><I>INSERT</I></TD>
<TD vAlign=top>NEW references are valid</TD></TR>
<TR>
<TD vAlign=top align=right width=120><I>UPDATE</I></TD>
<TD vAlign=top>NEW and OLD references are valid</TD></TR>
<TR>
<TD vAlign=top align=right width=120><I>DELETE</I></TD>
<TD vAlign=top>OLD references are valid</TD></TR></TBODY></TABLE>
<P></P>
<P>If a WHEN clause is supplied, the SQL statements specified as
<I>trigger-steps</I> are only executed for rows for which the WHEN clause is
true. If no WHEN clause is supplied, the SQL statements are executed for all
rows.</P>
<P>The specified <I>trigger-time</I> determines when the <I>trigger-steps</I>
will be executed relative to the insertion, modification or removal of the
associated row.</P>
<P>An ON CONFLICT clause may be specified as part of an UPDATE or INSERT
<I>trigger-step</I>. However if an ON CONFLICT clause is specified as part of
the statement causing the trigger to fire, then this conflict handling policy is
used instead.</P>
<P>Triggers are automatically dropped when the table that they are associated
with is dropped.</P>
<P>Triggers may be created on views, as well as ordinary tables, by specifying
INSTEAD OF in the CREATE TRIGGER statement. If one or more ON INSERT, ON DELETE
or ON UPDATE triggers are defined on a view, then it is not an error to execute
an INSERT, DELETE or UPDATE statement on the view, respectively. Thereafter,
executing an INSERT, DELETE or UPDATE on the view causes the associated triggers
to fire. The real tables underlying the view are not modified (except possibly
explicitly, by a trigger program).</P>
<P><B>Example:</B></P>
<P>Assuming that customer records are stored in the "customers" table, and that
order records are stored in the "orders" table, the following trigger ensures
that all associated orders are redirected when a customer changes his or her
address:</P>
<BLOCKQUOTE><PRE>CREATE TRIGGER update_customer_address UPDATE OF address ON customers
BEGIN
UPDATE orders SET address = new.address WHERE customer_name = old.name;
END;
</PRE></BLOCKQUOTE>
<P>With this trigger installed, executing the statement:</P>
<BLOCKQUOTE><PRE>UPDATE customers SET address = '1 Main St.' WHERE name = 'Jack Jones';
</PRE></BLOCKQUOTE>
<P>causes the following to be automatically executed:</P>
<BLOCKQUOTE><PRE>UPDATE orders SET address = '1 Main St.' WHERE customer_name = 'Jack Jones';
</PRE></BLOCKQUOTE>
<P>Note that currently, triggers may behave oddly when created on tables with
INTEGER PRIMARY KEY fields. If a BEFORE trigger program modifies the INTEGER
PRIMARY KEY field of a row that will be subsequently updated by the statement
that causes the trigger to fire, then the update may not occur. The workaround
is to declare the table with a PRIMARY KEY column instead of an INTEGER PRIMARY
KEY column.</P>
<P>A special SQL function RAISE() may be used within a trigger-program, with the
following syntax</P>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>raise-function</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>RAISE <BIG>(</BIG> ABORT<BIG>,</BIG>
</FONT></B><I><FONT color=#ff3434>error-message</FONT></I><B><FONT
color=#2c2cf0> <BIG>)</BIG> </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
<BR>RAISE <BIG>(</BIG> FAIL<BIG>,</BIG> </FONT></B><I><FONT
color=#ff3434>error-message</FONT></I><B><FONT color=#2c2cf0> <BIG>)</BIG>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> <BR>RAISE <BIG>(</BIG>
ROLLBACK<BIG>,</BIG> </FONT></B><I><FONT
color=#ff3434>error-message</FONT></I><B><FONT color=#2c2cf0> <BIG>)</BIG>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> <BR>RAISE <BIG>(</BIG>
IGNORE <BIG>)</BIG></FONT></B></TD></TR></TBODY></TABLE>
<P>When one of the first three forms is called during trigger-program execution,
the specified ON CONFLICT processing is performed (either ABORT, FAIL or
ROLLBACK) and the current query terminates. An error code of SQLITE_CONSTRAINT
is returned to the user, along with the specified error message.</P>
<P>When RAISE(IGNORE) is called, the remainder of the current trigger program,
the statement that caused the trigger program to execute and any subsequent
trigger programs that would of been executed are abandoned. No database changes
are rolled back. If the statement that caused the trigger program to execute is
itself part of a trigger program, then that trigger program resumes execution at
the beginning of the next step. </P>
<P>Triggers are removed using the <A
href="#droptrigger">DROP TRIGGER</A>
statement. Non-temporary triggers cannot be added on a table in an attached
database.</P>
<HR>
<A name=createview></A>
<H1>CREATE VIEW</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-command</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>CREATE </FONT></B>[<B><FONT color=#2c2cf0>TEMP
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
TEMPORARY</FONT></B>]<B><FONT color=#2c2cf0> VIEW </FONT></B><I><FONT
color=#ff3434>view-name</FONT></I><B><FONT color=#2c2cf0> AS
</FONT></B><I><FONT color=#ff3434>select-statement</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The CREATE VIEW command assigns a name to a pre-packaged <A
href="#select">SELECT</A> statement.
Once the view is created, it can be used in the FROM clause of another SELECT in
place of a table name. </P>
<P>You cannot COPY, DELETE, INSERT or UPDATE a view. Views are read-only in
SQLite. However, in many cases you can use a <A
href="#trigger">TRIGGER</A> on the view
to accomplish the same thing. Views are removed with the <A
href="#dropview">DROP VIEW</A> command.
Non-temporary views cannot be created on tables in an attached database.</P>
<HR>
<A name=delete></A>
<H1>DELETE</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>DELETE FROM </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0>WHERE </FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The DELETE command is used to remove records from a table. The command
consists of the "DELETE FROM" keywords followed by the name of the table from
which records are to be removed. </P>
<P>Without a WHERE clause, all rows of the table are removed. If a WHERE clause
is supplied, then only those rows that match the expression are removed.</P>
<HR>
<A name=detach></A>
<H1>DETACH DATABASE</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-command</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>DETACH </FONT></B>[<B><FONT
color=#2c2cf0>DATABASE</FONT></B>]<B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>database-name</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>This statement detaches an additional database connection previously attached
using the <A href="#attach">ATTACH
DATABASE</A> statement. It is possible to have the same database file attached
multiple times using different names, and detaching one connection to a file
will leave the others intact.</P>
<P>This statement will fail if SQLite is in the middle of a transaction.</P>
<HR>
<A name=dropindex></A>
<H1>DROP INDEX</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-command</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>DROP INDEX </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>index-name</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The DROP INDEX statement removes an index added with the <A
href="#createindex">CREATE INDEX</A>
statement. The index named is completely removed from the disk. The only way to
recover the index is to reenter the appropriate CREATE INDEX command.
Non-temporary indexes on tables in an attached database cannot be dropped.</P>
<P>The DROP INDEX statement does not reduce the size of the database file. Empty
space in the database is retained for later INSERTs. To remove free space in the
database, use the <A
href="#vacuum">VACUUM</A> command.</P>
<HR>
<A name=droptable></A>
<H1>DROP TABLE</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-command</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>DROP TABLE </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The DROP TABLE statement removes a table added with the <A
href="#createtable">CREATE TABLE</A>
statement. The name specified is the table name. It is completely removed from
the database schema and the disk file. The table can not be recovered. All
indices associated with the table are also deleted. Non-temporary tables in an
attached database cannot be dropped.</P>
<P>The DROP TABLE statement does not reduce the size of the database file. Empty
space in the database is retained for later INSERTs. To remove free space in the
database, use the <A
href="#vacuum">VACUUM</A> command.</P>
<HR>
<A name=droptrigger></A>
<H1>DROP TRIGGER</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>DROP TRIGGER </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>trigger-name</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The DROP TRIGGER statement removes a trigger created by the <A
href="#createtrigger">CREATE TRIGGER</A>
statement. The trigger is deleted from the database schema. Note that triggers
are automatically dropped when the associated table is dropped. Non-temporary
triggers cannot be dropped on attached tables.</P>
<HR>
<A name=dropview></A>
<H1>DROP VIEW</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-command</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>DROP VIEW </FONT></B><I><FONT
color=#ff3434>view-name</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The DROP VIEW statement removes a view created by the <A
href="#createview">CREATE VIEW</A>
statement. The name specified is the view name. It is removed from the database
schema, but no actual data in the underlying base tables is modified.
Non-temporary views in attached databases cannot be dropped.</P>
<HR>
<A name=explain></A>
<H1>EXPLAIN</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>EXPLAIN </FONT></B><I><FONT
color=#ff3434>sql-statement</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The EXPLAIN command modifier is a non-standard extension. The idea comes from
a similar command found in PostgreSQL, but the operation is completely
different.</P>
<P>If the EXPLAIN keyword appears before any other SQLite SQL command then
instead of actually executing the command, the SQLite library will report back
the sequence of virtual machine instructions it would have used to execute the
command had the EXPLAIN keyword not been present. For additional information
about virtual machine instructions see the <A
href="http://www.hwaci.com/sw/sqlite/arch.html">architecture description</A> or
the documentation on <A
href="http://www.hwaci.com/sw/sqlite/opcode.html">available opcodes</A> for the
virtual machine.</P>
<HR>
<A name=expr></A>
<H1>expression</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>expr</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>binary-op</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>like-op</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>unary-op</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR><BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0>
<BIG>)</BIG> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>column-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0> <BIG>.</BIG>
</FONT></B><I><FONT color=#ff3434>column-name</FONT></I><B><FONT
color=#2c2cf0> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0> <BIG>.</BIG>
</FONT></B><I><FONT color=#ff3434>table-name</FONT></I><B><FONT
color=#2c2cf0> <BIG>.</BIG> </FONT></B><I><FONT
color=#ff3434>column-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>literal-value</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>function-name</FONT></I><B><FONT color=#2c2cf0> <BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>expr-list</FONT></I><B><FONT
color=#2c2cf0> </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> <BIG>*</BIG>
<BIG>)</BIG> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> ISNULL
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> NOTNULL
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>NOT</FONT></B>]<B><FONT color=#2c2cf0> BETWEEN
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0>
AND </FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT
color=#2c2cf0> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>NOT</FONT></B>]<B><FONT color=#2c2cf0> IN <BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>value-list</FONT></I><B><FONT
color=#2c2cf0> <BIG>)</BIG> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>NOT</FONT></B>]<B><FONT color=#2c2cf0> IN <BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>select-statement</FONT></I><B><FONT
color=#2c2cf0> <BIG>)</BIG> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR></FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>NOT</FONT></B>]<B><FONT color=#2c2cf0> IN
</FONT></B>[<B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR><BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>select-statement</FONT></I><B><FONT
color=#2c2cf0> <BIG>)</BIG> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR>CASE </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B>(<B><FONT
color=#2c2cf0> WHEN </FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> THEN
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>)+<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>ELSE </FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0> END</FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>like-op</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>LIKE </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0> GLOB </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> NOT
LIKE </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> NOT
GLOB</FONT></B></TD></TR></TBODY></TABLE>
<P>This section is different from the others. Most other sections of this
document talks about a particular SQL command. This section does not talk about
a standalone command but about "expressions" which are subcomponents of most
other commands.</P>
<P>SQLite understands the following binary operators, in order from highest to
lowest precedence:</P>
<BLOCKQUOTE><PRE><FONT color=#2c2cf0><BIG>||
* / %
+ -
&lt;&lt; &gt;&gt; &amp; |
&lt; &lt;= &gt; &gt;=
= == != &lt;&gt; </BIG>IN
AND
OR</FONT>
</PRE></BLOCKQUOTE>
<P>Supported unary operaters are these:</P>
<BLOCKQUOTE><PRE><FONT color=#2c2cf0><BIG>- + ! ~</BIG></FONT>
</PRE></BLOCKQUOTE>
<P>Any SQLite value can be used as part of an expression. For arithmetic
operations, integers are treated as integers. Strings are first converted to
real numbers using <B>atof()</B>. For comparison operators, numbers compare as
numbers and strings compare using the <B>strcmp()</B> function. Note that there
are two variations of the equals and not equals operators. Equals can be either
<FONT color=#2c2cf0><BIG>=</BIG></FONT> or <FONT
color=#2c2cf0><BIG>==</BIG></FONT>. The non-equals operator can be either <FONT
color=#2c2cf0><BIG>!=</BIG></FONT> or <FONT
color=#2c2cf0><BIG>&lt;&gt;</BIG></FONT>. The <FONT
color=#2c2cf0><BIG>||</BIG></FONT> operator is "concatenate" - it joins together
the two strings of its operands. The operator <FONT
color=#2c2cf0><BIG>%</BIG></FONT> outputs the remainder of its left operand
modulo its right operand.</P><A name=like></A>
<P>The LIKE operator does a wildcard comparision. The operand to the right
contains the wildcards. A percent symbol <FONT color=#2c2cf0><BIG>%</BIG></FONT>
in the right operand matches any sequence of zero or more characters on the
left. An underscore <FONT color=#2c2cf0><BIG>_</BIG></FONT> on the right matches
any single character on the left. The LIKE operator is not case sensitive and
will match upper case characters on one side against lower case characters on
the other. (A bug: SQLite only understands upper/lower case for 7-bit Latin
characters. Hence the LIKE operator is case sensitive for 8-bit iso8859
characters or UTF-8 characters. For example, the expression
<B>'a'&nbsp;LIKE&nbsp;'A'</B> is TRUE but <B>'<27>'&nbsp;LIKE&nbsp;'<27>'</B> is
FALSE.). The infix LIKE operator is identical the user function <A
href="#likeFunc">like(<I>X</I>,<I>Y</I>)</A>.
</P><A name=glob></A>
<P>The GLOB operator is similar to LIKE but uses the Unix file globbing syntax
for its wildcards. Also, GLOB is case sensitive, unlike LIKE. Both GLOB and LIKE
may be preceded by the NOT keyword to invert the sense of the test. The infix
GLOB operator is identical the user function <A
href="#globFunc">glob(<I>X</I>,<I>Y</I>)</A>.</P>
<P>A column name can be any of the names defined in the CREATE TABLE statement
or one of the following special identifiers: "<B>ROWID</B>", "<B>OID</B>", or
"<B>_ROWID_</B>". These special identifiers all describe the unique random
integer key (the "row key") associated with every row of every table. The
special identifiers only refer to the row key if the CREATE TABLE statement does
not define a real column with the same name. Row keys act like read-only
columns. A row key can be used anywhere a regular column can be used, except
that you cannot change the value of a row key in an UPDATE or INSERT statement.
"SELECT * ..." does not return the row key.</P>
<P>SELECT statements can appear in expressions as either the right-hand operand
of the IN operator or as a scalar quantity. In both cases, the SELECT should
have only a single column in its result. Compound SELECTs (connected with
keywords like UNION or EXCEPT) are allowed. A SELECT in an expression is
evaluated once before any other processing is performed, so none of the
expressions within the select itself can refer to quantities in the containing
expression.</P>
<P>When a SELECT is the right operand of the IN operator, the IN operator
returns TRUE if the result of the left operand is any of the values generated by
the select. The IN operator may be preceded by the NOT keyword to invert the
sense of the test.</P>
<P>When a SELECT appears within an expression but is not the right operand of an
IN operator, then the first row of the result of the SELECT becomes the value
used in the expression. If the SELECT yields more than one result row, all rows
after the first are ignored. If the SELECT yeilds no rows, then the value of the
SELECT is NULL.</P>
<P>Both simple and aggregate functions are supported. A simple function can be
used in any expression. Simple functions return a result immediately based on
their inputs. Aggregate functions may only be used in a SELECT statement.
Aggregate functions compute their result across all rows of the result set.</P>
<P>The functions shown below are available by default. Additional functions may
be written in C and added to the database engine using the <A
href="http://www.hwaci.com/sw/sqlite/c_interface.html#cfunc">sqlite_create_function()</A>
API.</P>
<TABLE cellPadding=10 border=0>
<TBODY>
<TR>
<TD vAlign=top align=right width=120>abs(<I>X</I>)</TD>
<TD vAlign=top>Return the absolute value of argument <I>X</I>.</TD></TR>
<TR>
<TD vAlign=top align=right>coalesce(<I>X</I>,<I>Y</I>,...)</TD>
<TD vAlign=top>Return a copy of the first non-NULL argument. If all
arguments are NULL then NULL is returned. There must be at least 2
arguments.</TD></TR>
<TR><A name=globFunc></A>
<TD vAlign=top align=right>glob(<I>X</I>,<I>Y</I>)</TD>
<TD vAlign=top>This function is used to implement the "<B>Y GLOB X</B>"
syntax of SQLite. The <A
href="http://www.hwaci.com/sw/sqlite/c_interface.html#cfunc">sqlite_create_function()</A>
interface can be used to override this function and thereby change the
operation of the <A
href="#glob">GLOB</A>
operator.</TD></TR>
<TR>
<TD vAlign=top align=right>ifnull(<I>X</I>,<I>Y</I>)</TD>
<TD vAlign=top>Return a copy of the first non-NULL argument. If both
arguments are NULL then NULL is returned. This behaves the same as
<B>coalesce()</B> above.</TD></TR>
<TR>
<TD vAlign=top align=right>last_insert_rowid()</TD>
<TD vAlign=top>Return the ROWID of the last row insert from this
connection to the database. This is the same value that would be returned
from the <B>sqlite_last_insert_rowid()</B> API function.</TD></TR>
<TR>
<TD vAlign=top align=right>length(<I>X</I>)</TD>
<TD vAlign=top>Return the string length of <I>X</I> in characters. If
SQLite is configured to support UTF-8, then the number of UTF-8 characters
is returned, not the number of bytes.</TD></TR>
<TR><A name=likeFunc></A>
<TD vAlign=top align=right>like(<I>X</I>,<I>Y</I>)</TD>
<TD vAlign=top>This function is used to implement the "<B>Y LIKE X</B>"
syntax of SQL. The <A
href="http://www.hwaci.com/sw/sqlite/c_interface.html#cfunc">sqlite_create_function()</A>
interface can be used to override this function and thereby change the
operation of the <A
href="#like">LIKE</A>
operator.</TD></TR>
<TR>
<TD vAlign=top align=right>lower(<I>X</I>)</TD>
<TD vAlign=top>Return a copy of string <I>X</I> will all characters
converted to lower case. The C library <B>tolower()</B> routine is used
for the conversion, which means that this function might not work
correctly on UTF-8 characters.</TD></TR>
<TR>
<TD vAlign=top align=right>max(<I>X</I>,<I>Y</I>,...)</TD>
<TD vAlign=top>Return the argument with the maximum value. Arguments may
be strings in addition to numbers. The maximum value is determined by the
usual sort order. Note that <B>max()</B> is a simple function when it has
2 or more arguments but converts to an aggregate function if given only a
single argument.</TD></TR>
<TR>
<TD vAlign=top align=right>min(<I>X</I>,<I>Y</I>,...)</TD>
<TD vAlign=top>Return the argument with the minimum value. Arguments may
be strings in addition to numbers. The mminimum value is determined by the
usual sort order. Note that <B>min()</B> is a simple function when it has
2 or more arguments but converts to an aggregate function if given only a
single argument.</TD></TR>
<TR>
<TD vAlign=top align=right>nullif(<I>X</I>,<I>Y</I>)</TD>
<TD vAlign=top>Return the first argument if the arguments are different,
otherwise return NULL.</TD></TR>
<TR>
<TD vAlign=top align=right>random(*)</TD>
<TD vAlign=top>Return a random integer between -2147483648 and
+2147483647.</TD></TR>
<TR>
<TD vAlign=top align=right>round(<I>X</I>)<BR>round(<I>X</I>,<I>Y</I>)</TD>
<TD vAlign=top>Round off the number <I>X</I> to <I>Y</I> digits to the
right of the decimal point. If the <I>Y</I> argument is omitted, 0 is
assumed.</TD></TR>
<TR>
<TD vAlign=top align=right>soundex(<I>X</I>)</TD>
<TD vAlign=top>Compute the soundex encoding of the string <I>X</I>. The
string "?000" is returned if the argument is NULL. This function is
omitted from SQLite by default. It is only available the
-DSQLITE_SOUNDEX=1 compiler option is used when SQLite is built.</TD></TR>
<TR>
<TD vAlign=top align=right>sqlite_version(*)</TD>
<TD vAlign=top>Return the version string for the SQLite library that is
running. Example: "2.8.0"</TD></TR>
<TR>
<TD vAlign=top align=right>substr(<I>X</I>,<I>Y</I>,<I>Z</I>)</TD>
<TD vAlign=top>Return a substring of input string <I>X</I> that begins
with the <I>Y</I>-th character and which is <I>Z</I> characters long. The
left-most character of <I>X</I> is number 1. If <I>Y</I> is negative the
the first character of the substring is found by counting from the right
rather than the left. If SQLite is configured to support UTF-8, then
characters indices refer to actual UTF-8 characters, not bytes.</TD></TR>
<TR>
<TD vAlign=top align=right>typeof(<I>X</I>)</TD>
<TD vAlign=top>Return the type of the expression <I>X</I>. The only return
values are "numeric" and "text". SQLite's type handling is explained in <A
href="http://www.hwaci.com/sw/sqlite/datatypes.html">Datatypes in
SQLite</A>.</TD></TR>
<TR>
<TD vAlign=top align=right>upper(<I>X</I>)</TD>
<TD vAlign=top>Return a copy of input string <I>X</I> converted to all
upper-case letters. The implementation of this function uses the C library
routine <B>toupper()</B> which means it may not work correctly on UTF-8
strings.</TD></TR></TBODY></TABLE>
<P>The following aggregate functions are available by default. Additional
aggregate functions written in C may be added using the <A
href="http://www.hwaci.com/sw/sqlite/c_interface.html#cfunc">sqlite_create_aggregate()</A>
API.</P>
<TABLE cellPadding=10 border=0>
<TBODY>
<TR>
<TD vAlign=top align=right width=120>avg(<I>X</I>)</TD>
<TD vAlign=top>Return the average value of all <I>X</I> within a
group.</TD></TR>
<TR>
<TD vAlign=top align=right>count(<I>X</I>)<BR>count(*)</TD>
<TD vAlign=top>The first form return a count of the number of times that
<I>X</I> is not NULL in a group. The second form (with no argument)
returns the total number of rows in the group.</TD></TR>
<TR>
<TD vAlign=top align=right>max(<I>X</I>)</TD>
<TD vAlign=top>Return the maximum value of all values in the group. The
usual sort order is used to determine the maximum.</TD></TR>
<TR>
<TD vAlign=top align=right>min(<I>X</I>)</TD>
<TD vAlign=top>Return the minimum value of all values in the group. The
usual sort order is used to determine the minimum.</TD></TR>
<TR>
<TD vAlign=top align=right>sum(<I>X</I>)</TD>
<TD vAlign=top>Return the numeric sum of all values in the
group.</TD></TR></TBODY></TABLE>
<HR>
<A name=insert></A>
<H1>INSERT</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>INSERT </FONT></B>[<B><FONT color=#2c2cf0>OR
</FONT></B><I><FONT color=#ff3434>conflict-algorithm</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0> INTO
</FONT></B>[<B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0><BIG>(</BIG></FONT></B><I><FONT
color=#ff3434>column-list</FONT></I><B><FONT
color=#2c2cf0><BIG>)</BIG></FONT></B>]<B><FONT color=#2c2cf0>
VALUES<BIG>(</BIG></FONT></B><I><FONT
color=#ff3434>value-list</FONT></I><B><FONT color=#2c2cf0><BIG>)</BIG>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR>INSERT
</FONT></B>[<B><FONT color=#2c2cf0>OR </FONT></B><I><FONT
color=#ff3434>conflict-algorithm</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0> INTO
</FONT></B>[<B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0><BIG>(</BIG></FONT></B><I><FONT
color=#ff3434>column-list</FONT></I><B><FONT
color=#2c2cf0><BIG>)</BIG></FONT></B>]<B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>select-statement</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The INSERT statement comes in two basic forms. The first form (with the
"VALUES" keyword) creates a single new row in an existing table. If no
column-list is specified then the number of values must be the same as the
number of columns in the table. If a column-list is specified, then the number
of values must match the number of specified columns. Columns of the table that
do not appear in the column list are filled with the default value, or with NULL
if not default value is specified. </P>
<P>The second form of the INSERT statement takes it data from a SELECT
statement. The number of columns in the result of the SELECT must exactly match
the number of columns in the table if no column list is specified, or it must
match the number of columns name in the column list. A new entry is made in the
table for every row of the SELECT result. The SELECT may be simple or compound.
If the SELECT statement has an ORDER BY clause, the ORDER BY is ignored.</P>
<P>The optional conflict-clause allows the specification of an alternative
constraint conflict resolution algorithm to use during this one command. See the
section titled <A href="#conflict">ON
CONFLICT</A> for additional information. For compatibility with MySQL, the
parser allows the use of the single keyword <A
href="#replace">REPLACE</A> as an alias
for "INSERT OR REPLACE". </P>
<HR>
<A name=conflict></A>
<H1>ON CONFLICT clause</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>conflict-clause</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>ON CONFLICT </FONT></B><I><FONT
color=#ff3434>conflict-algorithm</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>conflict-algorithm</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>ROLLBACK </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0> ABORT </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> FAIL
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> IGNORE
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
REPLACE</FONT></B></TD></TR></TBODY></TABLE>
<P>The ON CONFLICT clause is not a separate SQL command. It is a non-standard
clause that can appear in many other SQL commands. It is given its own section
in this document because it is not part of standard SQL and therefore might not
be familiar.</P>
<P>The syntax for the ON CONFLICT clause is as shown above for the CREATE TABLE,
CREATE INDEX, and BEGIN TRANSACTION commands. For the COPY, INSERT, and UPDATE
commands, the keywords "ON CONFLICT" are replaced by "OR", to make the syntax
seem more natural. But the meaning of the clause is the same either way.</P>
<P>The ON CONFLICT clause specifies an algorithm used to resolve constraint
conflicts. There are five choices: ROLLBACK, ABORT, FAIL, IGNORE, and REPLACE.
The default algorithm is ABORT. This is what they mean:</P>
<DL>
<DT><B>ROLLBACK</B>
<DD>
<P>When a constraint violation occurs, an immediate ROLLBACK occurs, thus
ending the current transaction, and the command aborts with a return code of
SQLITE_CONSTRAINT. If no transaction is active (other than the implied
transaction that is created on every command) then this algorithm works the
same as ABORT.</P>
<DT><B>ABORT</B>
<DD>
<P>When a constraint violation occurs, the command backs out any prior changes
it might have made and aborts with a return code of SQLITE_CONSTRAINT. But no
ROLLBACK is executed so changes from prior commands within the same
transaction are preserved. This is the default behavior.</P>
<DT><B>FAIL</B>
<DD>
<P>When a constraint violation occurs, the command aborts with a return code
SQLITE_CONSTRAINT. But any changes to the database that the command made prior
to encountering the constraint violation are preserved and are not backed out.
For example, if an UPDATE statement encountered a constraint violation on the
100th row that it attempts to update, then the first 99 row changes are
preserved but changes to rows 100 and beyond never occur.</P>
<DT><B>IGNORE</B>
<DD>
<P>When a constraint violation occurs, the one row that contains the
constraint violation is not inserted or changed. But the command continues
executing normally. Other rows before and after the row that contained the
constraint violation continue to be inserted or updated normally. No error is
returned.</P>
<DT><B>REPLACE</B>
<DD>
<P>When a UNIQUE constraint violation occurs, the pre-existing rows that are
causing the constraint violation are removed prior to inserting or updating
the current row. Thus the insert or update always occurs. The command
continues executing normally. No error is returned. If a NOT NULL constraint
violation occurs, the NULL value is replaced by the default value for that
column. If the column has no default value, then the ABORT algorithm is
used.</P>
<P>When this conflict resolution strategy deletes rows in order to statisfy a
constraint, it does not invoke delete triggers on those rows. But that may
change in a future release.</P></DD></DL>
<P>The conflict resolution algorithm can be specified in three places, in order
from lowest to highest precedence: </P>
<OL>
<LI>
<P>On individual constraints within a CREATE TABLE or CREATE INDEX statement.
</P>
<LI>
<P>On a BEGIN TRANSACTION command. </P>
<LI>
<P>In the OR clause of a COPY, INSERT, or UPDATE command. </P></LI></OL>
<P>The algorithm specified in the OR clause of a COPY, INSERT, or UPDATE
overrides any algorithm specified on the BEGIN TRANSACTION command and the
algorithm specified on the BEGIN TRANSACTION command overrides the algorithm
specified in the a CREATE TABLE or CREATE INDEX. If no algorithm is specified
anywhere, the ABORT algorithm is used.</P>
<HR>
<A name=pragma></A>
<H1>PRAGMA</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>PRAGMA </FONT></B><I><FONT
color=#ff3434>name</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>= </FONT></B><I><FONT color=#ff3434>value</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0>
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0><BR>PRAGMA
</FONT></B><I><FONT color=#ff3434>function</FONT></I><B><FONT
color=#2c2cf0><BIG>(</BIG></FONT></B><I><FONT
color=#ff3434>arg</FONT></I><B><FONT
color=#2c2cf0><BIG>)</BIG></FONT></B></TD></TR></TBODY></TABLE>
<P>The PRAGMA command is used to modify the operation of the SQLite library. The
pragma command is experimental and specific pragma statements may be removed or
added in future releases of SQLite. Use this command with caution.</P>
<P>The pragmas that take an integer <B><I>value</I></B> also accept symbolic
names. The strings "<B>on</B>", "<B>true</B>", and "<B>yes</B>" are equivalent
to <B>1</B>. The strings "<B>off</B>", "<B>false</B>", and "<B>no</B>" are
equivalent to <B>0</B>. These strings are case- insensitive, and do not require
quotes. An unrecognized string will be treated as <B>1</B>, and will not
generate an error. When the <I>value</I> is returned it is as an integer.</P>
<P>The current implementation supports the following pragmas:</P>
<UL><A name=pragma_cache_size></A>
<LI>
<P><B>PRAGMA cache_size; <BR>PRAGMA cache_size =
</B><I>Number-of-pages</I><B>;</B></P>
<P>Query or change the maximum number of database disk pages that SQLite will
hold in memory at once. Each page uses about 1.5K of memory. The default cache
size is 2000. If you are doing UPDATEs or DELETEs that change many rows of a
database and you do not mind if SQLite uses more memory, you can increase the
cache size for a possible speed improvement.</P>
<P>When you change the cache size using the cache_size pragma, the change only
endures for the current session. The cache size reverts to the default value
when the database is closed and reopened. Use the <A
href="#pragma_default_cache_size"><B>default_cache_size</B></A>
pragma to check the cache size permanently.</P>
<LI>
<P><B>PRAGMA count_changes = ON; </B>(1)<B> <BR>PRAGMA count_changes =
OFF;</B> (0)</P>
<P>When on, the COUNT_CHANGES pragma causes the callback function to be
invoked once for each DELETE, INSERT, or UPDATE operation. The argument is the
number of rows that were changed.</P>
<P>This pragma may be removed from future versions of SQLite. Consider using
the <B>sqlite_changes()</B> API function instead.</P>
<LI>
<P><B>PRAGMA database_list;</B></P>
<P>For each open database, invoke the callback function once with information
about that database. Arguments include the index and the name the datbase was
attached with. The first row will be for the main database. The second row
will be for the database used to store temporary tables.</P><A
name=pragma_default_cache_size></A>
<LI>
<P><B>PRAGMA default_cache_size; <BR>PRAGMA default_cache_size =
</B><I>Number-of-pages</I><B>;</B></P>
<P>Query or change the maximum number of database disk pages that SQLite will
hold in memory at once. Each page uses 1K on disk and about 1.5K in memory.
This pragma works like the <A
href="#pragma_cache_size"><B>cache_size</B></A>
pragma with the additional feature that it changes the cache size
persistently. With this pragma, you can set the cache size once and that
setting is retained and reused everytime you reopen the database.</P><A
name=pragma_default_synchronous></A>
<LI>
<P><B>PRAGMA default_synchronous; <BR>PRAGMA default_synchronous = FULL;
</B>(2)<B> <BR>PRAGMA default_synchronous = NORMAL; </B>(1)<B> <BR>PRAGMA
default_synchronous = OFF; </B>(0)</P>
<P>Query or change the setting of the "synchronous" flag in the database. The
first (query) form will return the setting as an integer. When synchronous is
FULL (2), the SQLite database engine will pause at critical moments to make
sure that data has actually been written to the disk surface before
continuing. This ensures that if the operating system crashes or if there is a
power failure, the database will be uncorrupted after rebooting. FULL
synchronous is very safe, but it is also slow. When synchronous is NORMAL (1,
the default), the SQLite database engine will still pause at the most critical
moments, but less often than in FULL mode. There is a very small (though
non-zero) chance that a power failure at just the wrong time could corrupt the
database in NORMAL mode. But in practice, you are more likely to suffer a
catastrophic disk failure or some other unrecoverable hardware fault. So
NORMAL is the default mode. With synchronous OFF (0), SQLite continues without
pausing as soon as it has handed data off to the operating system. If the
application running SQLite crashes, the data will be safe, but the database
might become corrupted if the operating system crashes or the computer loses
power before that data has been written to the disk surface. On the other
hand, some operations are as much as 50 or more times faster with synchronous
OFF. </P>
<P>This pragma changes the synchronous mode persistently. Once changed, the
mode stays as set even if the database is closed and reopened. The <A
href="#pragma_synchronous"><B>synchronous</B></A>
pragma does the same thing but only applies the setting to the current
session.</P><A name=pragma_default_temp_store></A>
<LI>
<P><B>PRAGMA default_temp_store; <BR>PRAGMA default_temp_store = DEFAULT;
</B>(0)<B> <BR>PRAGMA default_temp_store = MEMORY; </B>(2)<B> <BR>PRAGMA
default_temp_store = FILE;</B> (1)</P>
<P>Query or change the setting of the "<B>temp_store</B>" flag stored in the
database. When temp_store is DEFAULT (0), the compile-time value of the symbol
TEMP_STORE is used for the temporary database. When temp_store is MEMORY (2),
an in-memory database is used. When temp_store is FILE (1), a temporary
database file on disk will be used. Once the temporary database is in use, its
location cannot be changed. It is possible for the library compile-time symbol
TEMP_STORE to override this setting. The following table summarizes this:</P>
<TABLE cellPadding=2>
<TBODY>
<TR>
<TH>TEMP_STORE</TH>
<TH>temp_store</TH>
<TH>temp database location</TH></TR>
<TR>
<TD align=middle>0</TD>
<TD align=middle><EM>any</EM></TD>
<TD align=middle>file</TD></TR>
<TR>
<TD align=middle>1</TD>
<TD align=middle>0</TD>
<TD align=middle>file</TD></TR>
<TR>
<TD align=middle>1</TD>
<TD align=middle>1</TD>
<TD align=middle>file</TD></TR>
<TR>
<TD align=middle>1</TD>
<TD align=middle>2</TD>
<TD align=middle>memory</TD></TR>
<TR>
<TD align=middle>2</TD>
<TD align=middle>0</TD>
<TD align=middle>memory</TD></TR>
<TR>
<TD align=middle>2</TD>
<TD align=middle>1</TD>
<TD align=middle>file</TD></TR>
<TR>
<TD align=middle>2</TD>
<TD align=middle>2</TD>
<TD align=middle>memory</TD></TR>
<TR>
<TD align=middle>3</TD>
<TD align=middle><EM>any</EM></TD>
<TD align=middle>memory</TD></TR></TBODY></TABLE>
<P>This pragma changes the temp_store mode persistently. Once changed, the
mode stays set even if the database is closed and reopened. The <A
href="#pragma_temp_store"><B>temp_store</B></A>
pragma does the same thing but only applies the setting to the current
session.</P><A name=pragma_empty_result_callbacks></A>
<LI>
<P><B>PRAGMA empty_result_callbacks = ON; </B>(1)<B> <BR>PRAGMA
empty_result_callbacks = OFF;</B> (0)</P>
<P>When on, the EMPTY_RESULT_CALLBACKS pragma causes the callback function to
be invoked once for each query that has an empty result set. The third
"<B>argv</B>" parameter to the callback is set to NULL because there is no
data to report. But the second "<B>argc</B>" and fourth "<B>columnNames</B>"
parameters are valid and can be used to determine the number and names of the
columns that would have been in the result set had the set not been empty.</P>
<LI>
<P><B>PRAGMA foreign_key_list(</B><I>table-name</I><B>);</B></P>
<P>For each foreign key that references a column in the argument table, invoke
the callback function with information about that foreign key. The callback
function will be invoked once for each column in each foreign key.</P>
<LI>
<P><B>PRAGMA full_column_names = ON; </B>(1)<B> <BR>PRAGMA full_column_names =
OFF;</B> (0)</P>
<P>The column names reported in an SQLite callback are normally just the name
of the column itself, except for joins when "TABLE.COLUMN" is used. But when
full_column_names is turned on, column names are always reported as
"TABLE.COLUMN" even for simple queries.</P>
<LI>
<P><B>PRAGMA index_info(</B><I>index-name</I><B>);</B></P>
<P>For each column that the named index references, invoke the callback
function once with information about that column, including the column name,
and the column number.</P>
<LI>
<P><B>PRAGMA index_list(</B><I>table-name</I><B>);</B></P>
<P>For each index on the named table, invoke the callback function once with
information about that index. Arguments include the index name and a flag to
indicate whether or not the index must be unique.</P>
<LI>
<P><B>PRAGMA integrity_check;</B></P>
<P>The command does an integrity check of the entire database. It looks for
out-of-order records, missing pages, malformed records, and corrupt indices.
If any problems are found, then a single string is returned which is a
description of all problems. If everything is in order, "ok" is returned.</P>
<LI>
<P><B>PRAGMA parser_trace = ON; </B>(1)<B> <BR>PRAGMA parser_trace = OFF;</B>
(0)</P>
<P>Turn tracing of the SQL parser inside of the SQLite library on and off.
This is used for debugging. This only works if the library is compiled without
the NDEBUG macro. </P><A name=pragma_show_datatypes></A>
<LI>
<P><B>PRAGMA show_datatypes = ON; </B>(1)<B> <BR>PRAGMA show_datatypes =
OFF;</B> (0)</P>
<P>When turned on, the SHOW_DATATYPES pragma causes extra entries containing
the names of <A
href="http://www.hwaci.com/sw/sqlite/datatypes.html">datatypes</A> of columns
to be appended to the 4th ("columnNames") argument to <B>sqlite_exec()</B>
callbacks. When turned off, the 4th argument to callbacks contains only the
column names. The datatype for table columns is taken from the CREATE TABLE
statement that defines the table. Columns with an unspecified datatype have a
datatype of "NUMERIC" and the results of expression have a datatype of either
"TEXT" or "NUMERIC" depending on the expression. The following chart
illustrates the difference for the query "SELECT 'xyzzy', 5, NULL AS empty
":</P>
<BLOCKQUOTE>
<TABLE border=0>
<TBODY>
<TR>
<TH>show_datatypes=OFF</TH>
<TH width=30></TH>
<TH>show_datatypes=ON</TH></TR>
<TR>
<TD vAlign=top>azCol[0] = "xyzzy";<BR>azCol[1] = "5";<BR>azCol[2] =
"empty";<BR>azCol[3] = 0; </TD>
<TD></TD>
<TD vAlign=top>azCol[0] = "xyzzy";<BR>azCol[1] = "5";<BR>azCol[2] =
"empty";<BR>azCol[3] = "TEXT";<BR>azCol[4] = "NUMERIC";<BR>azCol[5] =
"TEXT";<BR>azCol[6] = 0; </TD></TR></TBODY></TABLE></BLOCKQUOTE><A
name=pragma_synchronous></A>
<LI>
<P><B>PRAGMA synchronous; <BR>PRAGMA synchronous = FULL; </B>(2)<B> <BR>PRAGMA
synchronous = NORMAL; </B>(1)<B> <BR>PRAGMA synchronous = OFF;</B> (0)</P>
<P>Query or change the setting of the "synchronous" flag affecting the
database for the duration of the current database connection. The synchronous
flag reverts to its default value when the database is closed and reopened.
For additional information on the synchronous flag, see the description of the
<A
href="#pragma_default_synchronous"><B>default_synchronous</B></A>
pragma.</P>
<LI>
<P><B>PRAGMA table_info(</B><I>table-name</I><B>);</B></P>
<P>For each column in the named table, invoke the callback function once with
information about that column, including the column name, data type, whether
or not the column can be NULL, and the default value for the column.</P><A
name=pragma_temp_store></A>
<LI>
<P><B>PRAGMA temp_store; <BR>PRAGMA temp_store = DEFAULT; </B>(0)<B>
<BR>PRAGMA temp_store = MEMORY; </B>(2)<B> <BR>PRAGMA temp_store = FILE;</B>
(1)</P>
<P>Query or change the setting of the "temp_store" flag affecting the database
for the duration of the current database connection. The temp_store flag
reverts to its default value when the database is closed and reopened. For
additional information on the temp_store flag, see the description of the <A
href="#pragma_default_temp_store"><B>default_temp_store</B></A>
pragma. Note that it is possible for the library compile-time options to
override this setting. </P><A name=pragma_vdbe_trace></A>
<LI>
<P><B>PRAGMA vdbe_trace = ON; </B>(1)<B> <BR>PRAGMA vdbe_trace = OFF;</B>
(0)</P>
<P>Turn tracing of the virtual database engine inside of the SQLite library on
and off. This is used for debugging. See the <A
href="http://www.hwaci.com/sw/sqlite/vdbe.html#trace">VDBE documentation</A>
for more information.</P></LI></UL>
<P>No error message is generated if an unknown pragma is issued. Unknown pragmas
are ignored.</P>
<HR>
<A name=replace></A>
<H1>REPLACE</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>REPLACE INTO </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0><BIG>(</BIG> </FONT></B><I><FONT
color=#ff3434>column-list</FONT></I><B><FONT color=#2c2cf0>
<BIG>)</BIG></FONT></B>]<B><FONT color=#2c2cf0> VALUES <BIG>(</BIG>
</FONT></B><I><FONT color=#ff3434>value-list</FONT></I><B><FONT
color=#2c2cf0> <BIG>)</BIG> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR>REPLACE INTO </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0><BIG>(</BIG> </FONT></B><I><FONT
color=#ff3434>column-list</FONT></I><B><FONT color=#2c2cf0>
<BIG>)</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>select-statement</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The REPLACE command is an alias for the "INSERT OR REPLACE" variant of the <A
href="#insert">INSERT</A> command. This
alias is provided for compatibility with MySQL. See the <A
href="#insert">INSERT</A> command
documentation for additional information.</P>
<HR>
<A name=select></A>
<H1>SELECT</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>SELECT </FONT></B>[<B><FONT color=#2c2cf0>ALL
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
DISTINCT</FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>result</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0>FROM </FONT></B><I><FONT
color=#ff3434>table-list</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0><BR></FONT></B>[<B><FONT
color=#2c2cf0>WHERE </FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0><BR></FONT></B>[<B><FONT color=#2c2cf0>GROUP BY
</FONT></B><I><FONT color=#ff3434>expr-list</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0><BR></FONT></B>[<B><FONT
color=#2c2cf0>HAVING </FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0><BR></FONT></B>[<B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>compound-op</FONT></I><B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>select</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT
color=#2c2cf0><BR></FONT></B>[<B><FONT color=#2c2cf0>ORDER BY
</FONT></B><I><FONT color=#ff3434>sort-expr-list</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0><BR></FONT></B>[<B><FONT
color=#2c2cf0>LIMIT </FONT></B><I><FONT
color=#ff3434>integer</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0></FONT></B>(<B><FONT color=#2c2cf0>
OFFSET </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> <BIG>,</BIG>
</FONT></B>)<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>integer</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>result</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>result-column</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0><BIG>,</BIG> </FONT></B><I><FONT
color=#ff3434>result-column</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT
color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>result-column</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0><BIG>*</BIG> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0> <BIG>.</BIG>
<BIG>*</BIG> </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>AS</FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>string</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>]<B><FONT color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>table-list</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>table</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT color=#ff3434>join-op</FONT></I><B><FONT
color=#2c2cf0> </FONT></B><I><FONT color=#ff3434>table</FONT></I><B><FONT
color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>join-args</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT
color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>table</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0>AS </FONT></B><I><FONT
color=#ff3434>alias</FONT></I><B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0><BR><BIG>(</BIG> </FONT></B><I><FONT
color=#ff3434>select</FONT></I><B><FONT color=#2c2cf0> <BIG>)</BIG>
</FONT></B>[<B><FONT color=#2c2cf0>AS </FONT></B><I><FONT
color=#ff3434>alias</FONT></I><B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>join-op</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0><BIG>,</BIG> </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>NATURAL</FONT></B>]<B><FONT color=#2c2cf0>
</FONT></B>[<B><FONT color=#2c2cf0>LEFT </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0> RIGHT </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
FULL</FONT></B>]<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>OUTER </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> INNER
</FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0> CROSS</FONT></B>]<B><FONT
color=#2c2cf0> JOIN</FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>join-args</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B>[<B><FONT color=#2c2cf0>ON
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0>USING <BIG>(</BIG> </FONT></B><I><FONT
color=#ff3434>id-list</FONT></I><B><FONT color=#2c2cf0>
<BIG>)</BIG></FONT></B>]<B><FONT color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sort-expr-list</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>sort-order</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0><BIG>,</BIG> </FONT></B><I><FONT
color=#ff3434>expr</FONT></I><B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>sort-order</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT
color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sort-order</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>ASC </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0> DESC</FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>compound_op</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>UNION </FONT></B><BIG>|</BIG><B><FONT
color=#2c2cf0> UNION ALL </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
INTERSECT </FONT></B><BIG>|</BIG><B><FONT color=#2c2cf0>
EXCEPT</FONT></B></TD></TR></TBODY></TABLE>
<P>The SELECT statement is used to query the database. The result of a SELECT is
zero or more rows of data where each row has a fixed number of columns. The
number of columns in the result is specified by the expression list in between
the SELECT and FROM keywords. Any arbitrary expression can be used as a result.
If a result expression is <FONT color=#2c2cf0><BIG>*</BIG></FONT> then all
columns of all tables are substituted for that one expression. If the expression
is the name of a table followed by <FONT color=#2c2cf0><BIG>.*</BIG></FONT> then
the result is all columns in that one table.</P>
<P>The DISTINCT keyword causes a subset of result rows to be returned, in which
each result row is different. NULL values are not treated as distinct from
eachother. The default behavior is that all result rows be returned, which can
be made explicit with the keyword ALL.</P>
<P>The query is executed against one or more tables specified after the FROM
keyword. If multiple tables names are separated by commas, then the query is
against the cross join of the various tables. The full SQL-92 join syntax can
also be used to specify joins. A sub-query in parentheses may be substituted for
any table name in the FROM clause. The entire FROM clause may be omitted, in
which case the result is a single row consisting of the values of the expression
list. </P>
<P>The WHERE clause can be used to limit the number of rows over which the query
operates.</P>
<P>The GROUP BY clauses causes one or more rows of the result to be combined
into a single row of output. This is especially useful when the result contains
aggregate functions. The expressions in the GROUP BY clause do <EM>not</EM> have
to be expressions that appear in the result. The HAVING clause is similar to
WHERE except that HAVING applies after grouping has occurred. The HAVING
expression may refer to values, even aggregate functions, that are not in the
result.</P>
<P>The ORDER BY clause causes the output rows to be sorted. The argument to
ORDER BY is a list of expressions that are used as the key for the sort. The
expressions do not have to be part of the result for a simple SELECT, but in a
compound SELECT each sort expression must exactly match one of the result
columns. Each sort expression may be optionally followed by ASC or DESC to
specify the sort order.</P>
<P>The LIMIT clause places an upper bound on the number of rows returned in the
result. A negative LIMIT indicates no upper bound. The optional OFFSET following
LIMIT specifies how many rows to skip at the beginning of the result set. In a
compound query, the LIMIT clause may only appear on the final SELECT statement.
The limit is applied to the entire query not to the individual SELECT statement
to which it is attached. </P>
<P>A compound SELECT is formed from two or more simple SELECTs connected by one
of the operators UNION, UNION ALL, INTERSECT, or EXCEPT. In a compound SELECT,
all the constituent SELECTs must specify the same number of result columns.
There may be only a single ORDER BY clause at the end of the compound SELECT.
The UNION and UNION ALL operators combine the results of the SELECTs to the
right and left into a single big table. The difference is that in UNION all
result rows are distinct where in UNION ALL there may be duplicates. The
INTERSECT operator takes the intersection of the results of the left and right
SELECTs. EXCEPT takes the result of left SELECT after removing the results of
the right SELECT. When three are more SELECTs are connected into a compound,
they group from left to right.</P>
<HR>
<A name=update></A>
<H1>UPDATE</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>UPDATE </FONT></B>[<B><FONT color=#2c2cf0> OR
</FONT></B><I><FONT color=#ff3434>conflict-algorithm</FONT></I><B><FONT
color=#2c2cf0> </FONT></B>]<B><FONT color=#2c2cf0> </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>database-name</FONT></I><B><FONT color=#2c2cf0>
<BIG>.</BIG></FONT></B>]<B><FONT color=#2c2cf0> </FONT></B><I><FONT
color=#ff3434>table-name</FONT></I><B><FONT color=#2c2cf0><BR>SET
</FONT></B><I><FONT color=#ff3434>assignment</FONT></I><B><FONT
color=#2c2cf0> </FONT></B>[<B><FONT color=#2c2cf0><BIG>,</BIG>
</FONT></B><I><FONT color=#ff3434>assignment</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B><BIG>*</BIG><B><FONT
color=#2c2cf0><BR></FONT></B>[<B><FONT color=#2c2cf0>WHERE
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT color=#2c2cf0></FONT></B></TD></TR>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>assignment</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>column-name</FONT></I><B><FONT color=#2c2cf0> <BIG>=</BIG>
</FONT></B><I><FONT color=#ff3434>expr</FONT></I><B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The UPDATE statement is used to change the value of columns in selected rows
of a table. Each assignment in an UPDATE specifies a column name to the left of
the equals sign and an arbitrary expression to the right. The expressions may
use the values of other columns. All expressions are evaluated before any
assignments are made. A WHERE clause can be used to restrict which rows are
updated.</P>
<P>The optional conflict-clause allows the specification of an alternative
constraint conflict resolution algorithm to use during this one command. See the
section titled <A href="#conflict">ON
CONFLICT</A> for additional information.</P>
<HR>
<A name=vacuum></A>
<H1>VACUUM</H1>
<TABLE cellPadding=10>
<TBODY>
<TR>
<TD vAlign=top align=right><I><FONT
color=#ff3434>sql-statement</FONT></I>&nbsp;::=</TD>
<TD><B><FONT color=#2c2cf0>VACUUM </FONT></B>[<B><FONT
color=#2c2cf0></FONT></B><I><FONT
color=#ff3434>index-or-table-name</FONT></I><B><FONT
color=#2c2cf0></FONT></B>]<B><FONT
color=#2c2cf0></FONT></B></TD></TR></TBODY></TABLE>
<P>The VACUUM command is an SQLite extension modelled after a similar command
found in PostgreSQL. If VACUUM is invoked with the name of a table or index then
it is suppose to clean up the named table or index. In version 1.0 of SQLite,
the VACUUM command would invoke <B>gdbm_reorganize()</B> to clean up the backend
database file.</P>
<P>VACUUM became a no-op when the GDBM backend was removed from SQLITE in
version 2.0.0. VACUUM was reimplimented in version 2.8.1. The index or table
name argument is now ignored. </P>
<P>When an object (table, index, or trigger) is dropped from the database, it
leaves behind empty space. This makes the database file larger than it needs to
be, but can speed up inserts. In time inserts and deletes can leave the database
file structure fragmented, which slows down disk access to the database
contents. The VACUUM command cleans the database by copying its contents to a
temporary database file and reloading the original database file from the copy.
This eliminates free pages, aligns table data to be contiguous, and otherwise
cleans up the database file structure.</P>
<P>This command will fail if there is an active transaction. This command has no
effect on an in-memory database.</P>
<HR>
<A name=keywords></A>
<H1>SQLite keywords</H1>
<P>The following keywords are used by SQLite. Most are either reserved words in
SQL-92 or were listed as potential reserved words. Those which aren't are shown
in italics. Not all of these words are actually used by SQLite. Keywords are not
reserved in SQLite. Any keyword can be used as an identifier for SQLite objects
(columns, databases, indexes, tables, triggers, views, ...) but must generally
be enclosed by brackets or quotes to avoid confusing the parser. Keyword
matching in SQLite is case-insensitive.</P>
<P>Keywords can be used as identifiers in three ways:</P>
<TABLE>
<TBODY>
<TR>
<TD width="12%">'keyword'
<TD>Interpreted as a literal string if it occurs in a legal string
context, otherwise as an identifier.
<TR>
<TD>"keyword"
<TD>Interpreted as an identifier if it matches a known identifier and
occurs in a legal identifier context, otherwise as a string.
<TR>
<TD>[keyword]
<TD>Always interpreted as an identifer. (This notation is used by MS
Access and SQL Server.) </TR></TBODY></TABLE>
<H2>Fallback Keywords</H2>
<P>These keywords can be used as identifiers for SQLite objects without
delimiters.</P>
<P><I>ABORT</I> &nbsp;&nbsp; AFTER &nbsp;&nbsp; ASC &nbsp;&nbsp; <I>ATTACH</I>
&nbsp;&nbsp; BEFORE &nbsp;&nbsp; BEGIN &nbsp;&nbsp; DEFERRED &nbsp;&nbsp;
CASCADE &nbsp;&nbsp; <I>CLUSTER</I> &nbsp;&nbsp; <I>CONFLICT</I> &nbsp;&nbsp;
<I>COPY</I> &nbsp;&nbsp; CROSS &nbsp;&nbsp; <I>DATABASE</I> &nbsp;&nbsp;
<I>DELIMITERS</I> &nbsp;&nbsp; DESC &nbsp;&nbsp; <I>DETACH</I> &nbsp;&nbsp; EACH
&nbsp;&nbsp; END &nbsp;&nbsp; <I>EXPLAIN</I> &nbsp;&nbsp; <I>FAIL</I>
&nbsp;&nbsp; FOR &nbsp;&nbsp; FULL &nbsp;&nbsp; IGNORE &nbsp;&nbsp; IMMEDIATE
&nbsp;&nbsp; INITIALLY &nbsp;&nbsp; INNER &nbsp;&nbsp; <I>INSTEAD</I>
&nbsp;&nbsp; KEY &nbsp;&nbsp; LEFT &nbsp;&nbsp; MATCH &nbsp;&nbsp; NATURAL
&nbsp;&nbsp; OF &nbsp;&nbsp; <I>OFFSET</I> &nbsp;&nbsp; OUTER &nbsp;&nbsp;
<I>PRAGMA</I> &nbsp;&nbsp; <I>RAISE</I> &nbsp;&nbsp; <I>REPLACE</I> &nbsp;&nbsp;
RESTRICT &nbsp;&nbsp; RIGHT &nbsp;&nbsp; <I>ROW</I> &nbsp;&nbsp;
<I>STATEMENT</I> &nbsp;&nbsp; <I>TEMP</I> &nbsp;&nbsp; TEMPORARY &nbsp;&nbsp;
TRIGGER &nbsp;&nbsp; <I>VACUUM</I> &nbsp;&nbsp; VIEW &nbsp;&nbsp; </P>
<H2>Normal keywords</H2>
<P>These keywords can be used as identifiers for SQLite objects, but must be
enclosed in brackets or quotes for SQLite to recognize them as an
identifier.</P>
<P>ALL &nbsp;&nbsp; AND &nbsp;&nbsp; AS &nbsp;&nbsp; BETWEEN &nbsp;&nbsp; BY
&nbsp;&nbsp; CASE &nbsp;&nbsp; CHECK &nbsp;&nbsp; COLLATE &nbsp;&nbsp; COMMIT
&nbsp;&nbsp; CONSTRAINT &nbsp;&nbsp; CREATE &nbsp;&nbsp; DEFAULT &nbsp;&nbsp;
DEFERRABLE &nbsp;&nbsp; DELETE &nbsp;&nbsp; DISTINCT &nbsp;&nbsp; DROP
&nbsp;&nbsp; ELSE &nbsp;&nbsp; EXCEPT &nbsp;&nbsp; FOREIGN &nbsp;&nbsp; FROM
&nbsp;&nbsp; <I>GLOB</I> &nbsp;&nbsp; GROUP &nbsp;&nbsp; HAVING &nbsp;&nbsp; IN
&nbsp;&nbsp; <I>INDEX</I> &nbsp;&nbsp; INSERT &nbsp;&nbsp; INTERSECT
&nbsp;&nbsp; INTO &nbsp;&nbsp; IS &nbsp;&nbsp; <I>ISNULL</I> &nbsp;&nbsp; JOIN
&nbsp;&nbsp; LIKE &nbsp;&nbsp; LIMIT &nbsp;&nbsp; NOT &nbsp;&nbsp;
<I>NOTNULL</I> &nbsp;&nbsp; NULL &nbsp;&nbsp; ON &nbsp;&nbsp; OR &nbsp;&nbsp;
ORDER &nbsp;&nbsp; PRIMARY &nbsp;&nbsp; REFERENCES &nbsp;&nbsp; ROLLBACK
&nbsp;&nbsp; SELECT &nbsp;&nbsp; SET &nbsp;&nbsp; TABLE &nbsp;&nbsp; THEN
&nbsp;&nbsp; TRANSACTION &nbsp;&nbsp; UNION &nbsp;&nbsp; UNIQUE &nbsp;&nbsp;
UPDATE &nbsp;&nbsp; USING &nbsp;&nbsp; VALUES &nbsp;&nbsp; WHEN &nbsp;&nbsp;
WHERE &nbsp;&nbsp; </P>
<H2>Special words</H2>
<P>The following are not keywords in SQLite, but are used as names of system
objects. They can be used as an identifier for a different type of object.</P>
<P><I>_ROWID_</I> &nbsp;&nbsp; <I>MAIN</I> &nbsp;&nbsp; OID &nbsp;&nbsp;
<I>ROWID</I> &nbsp;&nbsp; <I>SQLITE_MASTER</I> &nbsp;&nbsp;
<I>SQLITE_TEMP_MASTER</I> &nbsp;&nbsp; </P>
<P>
<HR>
</BODY></HTML>
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