of the foreign-data
      wrapper, or of dependent servers, user mappings, or foreign tables, are
      invalid according to the new validator.  <productname>PostgreSQL</productname> does
      not check for this.  It is up to the user to make sure that these
      options are correct before using the modified foreign-data wrapper.
      However, any options specified in this <command>ALTER FOREIGN DATA
      WRAPPER</command> command will be checked using the new validator.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>NO VALIDATOR</literal></term>
    <listitem>
     <para>
      This is used to specify that the foreign-data wrapper should no
      longer have a validator function.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>OPTIONS ( [ ADD | SET | DROP ] <replaceable class="parameter">option</replaceable> ['<replaceable class="parameter">value</replaceable>'] [, ... ] )</literal></term>
    <listitem>
     <para>
      Change options for the foreign-data
      wrapper.  <literal>ADD</literal>, <literal>SET</literal>, and <literal>DROP</literal>
      specify the action to be performed.  <literal>ADD</literal> is assumed
      if no operation is explicitly specified.  Option names must be
      unique; names and values are also validated using the foreign
      data wrapper's validator function, if any.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">new_owner</replaceable></term>
    <listitem>
     <para>
      The user name of the new owner of the foreign-data wrapper.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">new_name</replaceable></term>
    <listitem>
     <para>
      The new name for the foreign-data wrapper.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   Change a foreign-data wrapper <literal>dbi</literal>, add
   option <literal>foo</literal>, drop <literal>bar</literal>:
<programlisting>
ALTER FOREIGN DATA WRAPPER dbi OPTIONS (ADD foo '1', DROP bar);
</programlisting>
  </para>

  <para>
   Change the foreign-data wrapper <literal>dbi</literal> validator
   to <literal>bob.myvalidator</literal>:
<programlisting>
ALTER FOREIGN DATA WRAPPER dbi VALIDATOR bob.myvalidator;
</programlisting></para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   <command>ALTER FOREIGN DATA WRAPPER</command> conforms to ISO/IEC
   9075-9 (SQL/MED), except that the <literal>HANDLER</literal>,
   <literal>VALIDATOR</literal>, <literal>OWNER TO</literal>, and <literal>RENAME</literal>
   clauses are extensions.
  </para>
 </refsect1>

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

  <simplelist type="inline">
   <member><xref linkend="sql-createforeigndatawrapper"/></member>
   <member><xref linkend="sql-dropforeigndatawrapper"/></member>
  </simplelist>
 </refsect1>

</refentry>