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

<refentry id="SQL-ALTEREXTENSION">
 <refmeta>
  <refentrytitle>ALTER EXTENSION</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ALTER EXTENSION</refname>
  <refpurpose>
   change the definition of an extension
  </refpurpose>
 </refnamediv>

 <indexterm zone="sql-alterextension">
  <primary>ALTER EXTENSION</primary>
 </indexterm>

 <refsynopsisdiv>
<synopsis>
ALTER EXTENSION <replaceable class="PARAMETER">extension_name</replaceable> UPDATE [ TO <replaceable class="PARAMETER">new_version</replaceable> ]
ALTER EXTENSION <replaceable class="PARAMETER">extension_name</replaceable> SET SCHEMA <replaceable class="PARAMETER">new_schema</replaceable>
ALTER EXTENSION <replaceable class="PARAMETER">extension_name</replaceable> ADD <replaceable class="PARAMETER">member_object</replaceable>
ALTER EXTENSION <replaceable class="PARAMETER">extension_name</replaceable> DROP <replaceable class="PARAMETER">member_object</replaceable>

<phrase>where <replaceable class="PARAMETER">member_object</replaceable> is:</phrase>

  AGGREGATE <replaceable class="PARAMETER">agg_name</replaceable> (<replaceable class="PARAMETER">agg_type</replaceable> [, ...] ) |
  CAST (<replaceable>source_type</replaceable> AS <replaceable>target_type</replaceable>) |
  COLLATION <replaceable class="PARAMETER">object_name</replaceable> |
  CONVERSION <replaceable class="PARAMETER">object_name</replaceable> |
  DOMAIN <replaceable class="PARAMETER">object_name</replaceable> |
  FOREIGN DATA WRAPPER <replaceable class="PARAMETER">object_name</replaceable> |
  FOREIGN TABLE <replaceable class="PARAMETER">object_name</replaceable> |
  FUNCTION <replaceable class="PARAMETER">function_name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) |
  OPERATOR <replaceable class="PARAMETER">operator_name</replaceable> (<replaceable class="PARAMETER">left_type</replaceable>, <replaceable class="PARAMETER">right_type</replaceable>) |
  OPERATOR CLASS <replaceable class="PARAMETER">object_name</replaceable> USING <replaceable class="parameter">index_method</replaceable> |
  OPERATOR FAMILY <replaceable class="PARAMETER">object_name</replaceable> USING <replaceable class="parameter">index_method</replaceable> |
  [ PROCEDURAL ] LANGUAGE <replaceable class="PARAMETER">object_name</replaceable> |
  SCHEMA <replaceable class="PARAMETER">object_name</replaceable> |
  SEQUENCE <replaceable class="PARAMETER">object_name</replaceable> |
  SERVER <replaceable class="PARAMETER">object_name</replaceable> |
  TABLE <replaceable class="PARAMETER">object_name</replaceable> |
  TEXT SEARCH CONFIGURATION <replaceable class="PARAMETER">object_name</replaceable> |
  TEXT SEARCH DICTIONARY <replaceable class="PARAMETER">object_name</replaceable> |
  TEXT SEARCH PARSER <replaceable class="PARAMETER">object_name</replaceable> |
  TEXT SEARCH TEMPLATE <replaceable class="PARAMETER">object_name</replaceable> |
  TYPE <replaceable class="PARAMETER">object_name</replaceable> |
  VIEW <replaceable class="PARAMETER">object_name</replaceable>
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER EXTENSION</command> changes the definition of an installed
   extension.  There are several subforms:

   <variablelist>
   <varlistentry>
    <term><literal>UPDATE</literal></term>
    <listitem>
     <para>
      This form updates the extension to a newer version.  The extension
      must supply a suitable update script (or series of scripts) that can
      modify the currently-installed version into the requested version.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>SET SCHEMA</literal></term>
    <listitem>
     <para>
      This form moves the extension's objects into another schema. The
      extension has to be <firstterm>relocatable</> for this command to
      succeed.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>ADD <replaceable class="PARAMETER">member_object</replaceable></literal></term>
    <listitem>
     <para>
      This form adds an existing object to the extension.  This is mainly
      useful in extension update scripts.  The object will subsequently
      be treated as a member of the extension; notably, it can only be
      dropped by dropping the extension.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>DROP <replaceable class="PARAMETER">member_object</replaceable></literal></term>
    <listitem>
     <para>
      This form removes a member object from the extension.  This is mainly
      useful in extension update scripts.  The object is not dropped, only
      disassociated from the extension.
     </para>
    </listitem>
   </varlistentry>
   </variablelist>

   See <xref linkend="extend-extensions"> for more information about these
   operations.
  </para>

  <para>
   You must own the extension to use <command>ALTER EXTENSION</command>.
   The <literal>ADD</>/<literal>DROP</> forms require ownership of the
   added/dropped object as well.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <para>
   <variablelist>
    <varlistentry>
     <term><replaceable class="PARAMETER">extension_name</replaceable></term>
     <listitem>
      <para>
       The name of an installed extension.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable class="PARAMETER">new_version</replaceable></term>
     <listitem>
      <para>
       The desired new version of the extension.  This can be written as
       either an identifier or a string literal.  If not specified,
       <command>ALTER EXTENSION UPDATE</> attempts to update to whatever is
       shown as the default version in the extension's control file.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable class="PARAMETER">new_schema</replaceable></term>
     <listitem>
      <para>
       The new schema for the extension.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable class="parameter">object_name</replaceable></term>
     <term><replaceable class="parameter">agg_name</replaceable></term>
     <term><replaceable class="parameter">function_name</replaceable></term>
     <term><replaceable class="parameter">operator_name</replaceable></term>
     <listitem>
      <para>
       The name of an object to be added to or removed from the extension.
       Names of tables,
       aggregates, domains, foreign tables, functions, operators,
       operator classes, operator families, sequences, text search objects,
       types, and views can be schema-qualified.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable class="parameter">agg_type</replaceable></term>
     <listitem>
      <para>
       An input data type on which the aggregate function operates.
       To reference a zero-argument aggregate function, write <literal>*</>
       in place of the list of input data types.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable>source_type</replaceable></term>
     <listitem>
      <para>
       The name of the source data type of the cast.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable>target_type</replaceable></term>
     <listitem>
      <para>
       The name of the target data type of the cast.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable class="parameter">argmode</replaceable></term>

     <listitem>
      <para>
       The mode of a function argument: <literal>IN</>, <literal>OUT</>,
       <literal>INOUT</>, or <literal>VARIADIC</>.
       If omitted, the default is <literal>IN</>.
       Note that <command>ALTER EXTENSION</command> does not actually pay
       any attention to <literal>OUT</> arguments, since only the input
       arguments are needed to determine the function's identity.
       So it is sufficient to list the <literal>IN</>, <literal>INOUT</>,
       and <literal>VARIADIC</> arguments.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable class="parameter">argname</replaceable></term>

     <listitem>
      <para>
       The name of a function argument.
       Note that <command>ALTER EXTENSION</command> does not actually pay
       any attention to argument names, since only the argument data
       types are needed to determine the function's identity.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable class="parameter">argtype</replaceable></term>

     <listitem>
      <para>
       The data type(s) of the function's arguments (optionally
       schema-qualified), if any.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><replaceable class="parameter">left_type</replaceable></term>
     <term><replaceable class="parameter">right_type</replaceable></term>
     <listitem>
      <para>
       The data type(s) of the operator's arguments (optionally
       schema-qualified).  Write <literal>NONE</> for the missing argument
       of a prefix or postfix operator.
      </para>
     </listitem>
    </varlistentry>

    <varlistentry>
     <term><literal>PROCEDURAL</literal></term>

     <listitem>
      <para>
       This is a noise word.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   To update the <literal>hstore</literal> extension to version 2.0:
<programlisting>
ALTER EXTENSION hstore UPDATE TO '2.0';
</programlisting>
  </para>

  <para>
   To change the schema of the <literal>hstore</literal> extension
   to <literal>utils</literal>:
<programlisting>
ALTER EXTENSION hstore SET SCHEMA utils;
</programlisting>
  </para>

  <para>
   To add an existing function to the <literal>hstore</literal> extension:
<programlisting>
ALTER EXTENSION hstore ADD FUNCTION populate_record(anyelement, hstore);
</programlisting></para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   <command>ALTER EXTENSION</command> is a <productname>PostgreSQL</>
   extension.
  </para>
 </refsect1>

 <refsect1 id="SQL-ALTEREXTENSION-see-also">
  <title>See Also</title>

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