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

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

 <refnamediv>
  <refname>ALTER VIEW</refname>
  <refpurpose>change the definition of a view</refpurpose>
 </refnamediv>  
  
 <indexterm zone="sql-alterview">
  <primary>ALTER VIEW</primary>
 </indexterm>

 <refsynopsisdiv>
<synopsis>
ALTER VIEW <replaceable class="parameter">name</replaceable> ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> SET DEFAULT <replaceable class="PARAMETER">expression</replaceable>
ALTER VIEW <replaceable class="parameter">name</replaceable> ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> DROP DEFAULT
ALTER VIEW <replaceable class="parameter">name</replaceable> OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
ALTER VIEW <replaceable class="parameter">name</replaceable> RENAME TO <replaceable class="parameter">new_name</replaceable>
ALTER VIEW <replaceable class="parameter">name</replaceable> SET SCHEMA <replaceable class="parameter">new_schema</replaceable>
</synopsis>
 </refsynopsisdiv>
  
 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER VIEW</command> changes various auxiliary properties
   of a view.  (If you want to modify the view's defining query,
   use <command>CREATE OR REPLACE VIEW</>.)
  </para>

  <para>
   You must own the view to use <command>ALTER VIEW</>.
   To change a view's schema, you must also have <literal>CREATE</>
   privilege on the new schema.
   To alter the owner, you must also be a direct or indirect member of the new
   owning role, and that role must have <literal>CREATE</literal> privilege on
   the view's schema.  (These restrictions enforce that altering the owner
   doesn't do anything you couldn't do by dropping and recreating the view.
   However, a superuser can alter ownership of any view anyway.)
  </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 view.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>SET</literal>/<literal>DROP DEFAULT</literal></term>
    <listitem>
     <para>
      These forms set or remove the default value for a column.
      A default value associated with a view column is
      inserted into <command>INSERT</> statements on the view before
      the view's <literal>ON INSERT</literal> rule is applied, if
      the <command>INSERT</> does not specify a value for the column.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="PARAMETER">new_owner</replaceable></term>
    <listitem>
     <para>
      The user name of the new owner of the view.
     </para>
    </listitem>
   </varlistentry>

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

   <varlistentry>
    <term><replaceable class="parameter">new_schema</replaceable></term>
    <listitem>
     <para>
      The new schema for the view.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   For historical reasons, <command>ALTER TABLE</command> can be used with
   views too; but the only variants of <command>ALTER TABLE</command>
   that are allowed with views are equivalent to the ones shown above.
  </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   To rename the view <literal>foo</literal> to
   <literal>bar</literal>:
<programlisting>
ALTER VIEW foo RENAME TO bar;
</programlisting>
  </para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

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

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

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