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<refentry id="SQL-ALTERFUNCTION">
 <refmeta>
  <refentrytitle id="SQL-ALTERFUNCTION-TITLE">ALTER FUNCTION</refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ALTER FUNCTION</refname>
  <refpurpose>change the definition of a function</refpurpose>
 </refnamediv>  
  
 <indexterm zone="sql-alterfunction">
  <primary>ALTER FUNCTION</primary>
 </indexterm>

 <refsynopsisdiv>
<synopsis>
ALTER FUNCTION <replaceable>name</replaceable> ( [ <replaceable class="parameter">type</replaceable> [, ...] ] ) RENAME TO <replaceable>newname</replaceable>
</synopsis>
 </refsynopsisdiv>
  
 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER FUNCTION</command> changes the definition of a
   function.  The only functionality is to rename the function.
  </para>
 </refsect1>
  
 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="parameter">name</replaceable></term>
    <listitem>
     <para>
      The name (optionally schema-qualified) of an existing function.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">type</replaceable></term>
    <listitem>
     <para>
      The data type of an argument of the function.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">newname</replaceable></term>
    <listitem>
     <para>
      The new name of the function.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   To rename the function <literal>sqrt</literal> for type
   <type>integer</type> to <literal>square_root</literal>:
<programlisting>
ALTER FUNCTION sqrt(integer) RENAME TO square_root;
</programlisting>
  </para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   There is an <command>ALTER FUNCTION</command> statement in the SQL
   standard, but it does not provide the option to rename the
   function.
  </para>
 </refsect1>

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

  <simplelist type="inline">
   <member><xref linkend="sql-createfunction" endterm="sql-createfunction-title"></member>
   <member><xref linkend="sql-dropfunction" endterm="sql-dropfunction-title"></member>
  </simplelist>
 </refsect1>
</refentry>

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