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<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/rollback_to.sgml,v 1.1 2004/08/01 17:32:13 tgl Exp $
PostgreSQL documentation
-->
<refentry id="SQL-ROLLBACK-TO">
<refmeta>
<refentrytitle id="SQL-ROLLBACK-TO-TITLE">ROLLBACK TO</refentrytitle>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>ROLLBACK TO</refname>
<refpurpose>roll back to a savepoint</refpurpose>
</refnamediv>
<indexterm zone="sql-rollback-to">
<primary>ROLLBACK TO</primary>
</indexterm>
<indexterm zone="sql-rollback-to">
<primary>savepoints</primary>
<secondary>rolling back</secondary>
</indexterm>
<refsynopsisdiv>
<synopsis>
ROLLBACK TO <replaceable>savepoint_name</replaceable>
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
Roll back all commands that were executed after the savepoint was
established. The savepoint remains valid and can be rolled back to
again later, if needed.
</para>
<para>
<command>ROLLBACK TO</> implicitly destroys all savepoints that
were established after the named savepoint.
</para>
</refsect1>
<refsect1>
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><replaceable class="PARAMETER">savepoint_name</></term>
<listitem>
<para>
The savepoint to roll back to.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Notes</title>
<para>
Use <xref linkend="SQL-RELEASE" endterm="SQL-RELEASE-TITLE"> to
destroy a savepoint without discarding the effects of commands executed
after it was established.
</para>
<para>
Specifying a savepoint name that has not been established is an error.
</para>
<para>
Cursors have somewhat non-transactional behavior with respect to
savepoints. Any cursor that is opened inside the savepoint is not closed
when the savepoint is rolled back. If a cursor is affected by a
<command>FETCH</> command inside a savepoint that is later rolled
back, the cursor position remains at the position that <command>FETCH</>
left it pointing to (that is, <command>FETCH</> is not rolled back).
A cursor whose execution causes a transaction to abort is put in a
can't-execute state, so while the transaction can be restored using
<command>ROLLBACK TO</>, the cursor can no longer be used.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
To undo the effects of the commands executed after <literal>my_savepoint</literal>
was established:
<programlisting>
ROLLBACK TO my_savepoint;
</programlisting>
</para>
<para>
Cursor positions are not affected by savepoint rollback:
<programlisting>
BEGIN;
DECLARE foo CURSOR FOR SELECT 1 UNION SELECT 2;
SAVEPOINT foo;
FETCH 1 FROM foo;
?column?
----------
1
ROLLBACK TO foo;
FETCH 1 FROM foo;
?column?
----------
2
COMMIT;
</programlisting>
</para>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
This command is fully SQL standard conforming.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-begin" endterm="sql-begin-title"></member>
<member><xref linkend="sql-commit" endterm="sql-commit-title"></member>
<member><xref linkend="sql-savepoint" endterm="sql-savepoint-title"></member>
<member><xref linkend="sql-release" endterm="sql-release-title"></member>
<member><xref linkend="sql-rollback" endterm="sql-rollback-title"></member>
</simplelist>
</refsect1>
</refentry>
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sgml-minimize-attributes:nil
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