versions.
   See <filename>src/backend/utils/fmgr/README</filename> for more
   information.
  </para>

 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   This example creates a composite type and uses it in
   a function definition:
<programlisting>
CREATE TYPE compfoo AS (f1 int, f2 text);

CREATE FUNCTION getfoo() RETURNS SETOF compfoo AS $$
    SELECT fooid, fooname FROM foo
$$ LANGUAGE SQL;
</programlisting>
  </para>

  <para>
   This example creates an enumerated type and uses it in
   a table definition:
<programlisting>
CREATE TYPE bug_status AS ENUM ('new', 'open', 'closed');

CREATE TABLE bug (
    id serial,
    description text,
    status bug_status
);
</programlisting>
  </para>

  <para>
   This example creates a range type:
<programlisting>
CREATE TYPE float8_range AS RANGE (subtype = float8, subtype_diff = float8mi);
</programlisting>
  </para>

  <para>
   This example creates the base data type <type>box</type> and then uses the
   type in a table definition:
<programlisting>
CREATE TYPE box;

CREATE FUNCTION my_box_in_function(cstring) RETURNS box AS ... ;
CREATE FUNCTION my_box_out_function(box) RETURNS cstring AS ... ;

CREATE TYPE box (
    INTERNALLENGTH = 16,
    INPUT = my_box_in_function,
    OUTPUT = my_box_out_function
);

CREATE TABLE myboxes (
    id integer,
    description box
);
</programlisting>
  </para>

  <para>
   If the internal structure of <type>box</type> were an array of four
   <type>float4</type> elements, we might instead use:
<programlisting>
CREATE TYPE box (
    INTERNALLENGTH = 16,
    INPUT = my_box_in_function,
    OUTPUT = my_box_out_function,
    ELEMENT = float4
);
</programlisting>
   which would allow a box value's component numbers to be accessed
   by subscripting.  Otherwise the type behaves the same as before.
  </para>

  <para>
   This example creates a large object type and uses it in
   a table definition:
<programlisting>
CREATE TYPE bigobj (
    INPUT = lo_filein, OUTPUT = lo_fileout,
    INTERNALLENGTH = VARIABLE
);
CREATE TABLE big_objs (
    id integer,
    obj bigobj
);
</programlisting>
  </para>

  <para>
   More examples, including suitable input and output functions, are
   in <xref linkend="xtypes"/>.
  </para>
 </refsect1>

 <refsect1 id="sql-createtype-compatibility">
  <title>Compatibility</title>

  <para>
   The first form of the <command>CREATE TYPE</command> command, which
   creates a composite type, conforms to the <acronym>SQL</acronym> standard.
   The other forms are <productname>PostgreSQL</productname>
   extensions.  The <command>CREATE TYPE</command> statement in
   the <acronym>SQL</acronym> standard also defines other forms that are not
   implemented in <productname>PostgreSQL</productname>.
  </para>

  <para>
   The ability to create a composite type with zero attributes is
   a <productname>PostgreSQL</productname>-specific deviation from the
   standard (analogous to the same case in <command>CREATE TABLE</command>).
  </para>
 </refsect1>

 <refsect1 id="sql-createtype-see-also">
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-altertype"/></member>
   <member><xref linkend="sql-createdomain"/></member>
   <member><xref linkend="sql-createfunction"/></member>
   <member><xref linkend="sql-droptype"/></member>
  </simplelist>
 </refsect1>

</refentry>