<!--
doc/src/sgml/ref/rollback.sgml
PostgreSQL documentation
-->

<refentry id="sql-rollback">
 <indexterm zone="sql-rollback">
  <primary>ROLLBACK</primary>
 </indexterm>

 <refmeta>
  <refentrytitle>ROLLBACK</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ROLLBACK</refname>
  <refpurpose>abort the current transaction</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
ROLLBACK [ WORK | TRANSACTION ] [ AND [ NO ] CHAIN ]
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ROLLBACK</command> rolls back the current transaction and causes
   all the updates made by the transaction to be discarded.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <indexterm zone="sql-rollback-chain">
   <primary>chained transactions</primary>
  </indexterm>

  <variablelist>
   <varlistentry>
    <term><literal>WORK</literal></term>
    <term><literal>TRANSACTION</literal></term>
    <listitem>
     <para>
      Optional key words. They have no effect.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry id="sql-rollback-chain">
    <term><literal>AND CHAIN</literal></term>
    <listitem>
     <para>
      If <literal>AND CHAIN</literal> is specified, a new transaction is
      immediately started with the same transaction characteristics (see <xref
      linkend="sql-set-transaction"/>) as the just finished one.  Otherwise,
      no new transaction is started.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   Use <xref linkend="sql-commit"/> to
   successfully terminate a transaction.
  </para>

  <para>
   Issuing <command>ROLLBACK</command> outside of a transaction
   block emits a warning and otherwise has no effect.  <command>ROLLBACK AND
   CHAIN</command> outside of a transaction block is an error.
  </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   To abort all changes:
<programlisting>
ROLLBACK;
</programlisting></para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   The command <command>ROLLBACK</command> conforms to the SQL standard.  The
   form <literal>ROLLBACK TRANSACTION</literal> is a PostgreSQL extension.
  </para>
 </refsect1>

 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-begin"/></member>
   <member><xref linkend="sql-commit"/></member>
   <member><xref linkend="sql-rollback-to"/></member>
  </simplelist>
 </refsect1>
</refentry>
