<!--
doc/src/sgml/ref/alter_trigger.sgml
PostgreSQL documentation
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<refentry id="sql-altertrigger">
 <indexterm zone="sql-altertrigger">
  <primary>ALTER TRIGGER</primary>
 </indexterm>

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

 <refnamediv>
  <refname>ALTER TRIGGER</refname>
  <refpurpose>change the definition of a trigger</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
ALTER TRIGGER <replaceable class="parameter">name</replaceable> ON <replaceable class="parameter">table_name</replaceable> RENAME TO <replaceable class="parameter">new_name</replaceable>
ALTER TRIGGER <replaceable class="parameter">name</replaceable> ON <replaceable class="parameter">table_name</replaceable> [ NO ] DEPENDS ON EXTENSION <replaceable class="parameter">extension_name</replaceable>
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER TRIGGER</command> changes properties of an existing
   trigger.  The <literal>RENAME</literal> clause changes the name of
   the given trigger without otherwise changing the trigger
   definition.  The <literal>DEPENDS ON EXTENSION</literal> clause marks
   the trigger as dependent on an extension, such that if the extension is
   dropped, the trigger will automatically be dropped as well.
  </para>

  <para>
   You must own the table on which the trigger acts to be allowed to change its properties.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="parameter">name</replaceable></term>
    <listitem>
     <para>
      The name of an existing trigger to alter.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">table_name</replaceable></term>
    <listitem>
     <para>
      The name of the table on which this trigger acts.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">new_name</replaceable></term>
    <listitem>
     <para>
      The new name for the trigger.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">extension_name</replaceable></term>
    <listitem>
     <para>
      The name of the extension that the trigger is to depend on (or no longer
      dependent on, if <literal>NO</literal> is specified).  A trigger
      that's marked as dependent on an extension is automatically dropped when
      the extension is dropped.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

   <para>
    The ability to temporarily enable or disable a trigger is provided by
    <link linkend="sql-altertable"><command>ALTER TABLE</command></link>, not by
    <command>ALTER TRIGGER</command>, because <command>ALTER TRIGGER</command> has no
    convenient way to express the option of enabling or disabling all of
    a table's triggers at once.
   </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   To rename an existing trigger:
<programlisting>
ALTER TRIGGER emp_stamp ON emp RENAME TO emp_track_chgs;
</programlisting></para>

  <para>
   To mark a trigger as being dependent on an extension:
<programlisting>
ALTER TRIGGER emp_stamp ON emp DEPENDS ON EXTENSION emplib;
</programlisting></para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   <command>ALTER TRIGGER</command> is a <productname>PostgreSQL</productname>
   extension of the SQL standard.
  </para>
 </refsect1>

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

  <simplelist type="inline">
   <member><xref linkend="sql-altertable"/></member>
  </simplelist>
 </refsect1>
</refentry>
