Index: doc/src/sgml/datatype.sgml
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RCS file: /var/lib/cvs/pgsql-server/doc/src/sgml/datatype.sgml,v
retrieving revision 1.109
diff -c -r1.109 datatype.sgml
*** doc/src/sgml/datatype.sgml	21 Nov 2002 23:31:20 -0000	1.109
--- doc/src/sgml/datatype.sgml	5 Dec 2002 00:32:52 -0000
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*** 654,663 ****
      </indexterm>
  
      <para>
!      The <type>serial</type> data types are not truly types, but are a
!      notational convenience for setting up unique identifier columns
!      in tables.
!      In the current implementation, specifying
  
  <programlisting>
  CREATE TABLE <replaceable class="parameter">tablename</replaceable> (
--- 654,664 ----
      </indexterm>
  
      <para>
!      The <type>serial</type> data type is not a true type, but merely
!      a notational convenience for setting up identifier columns
!      (similar to the <literal>AUTO_INCREMENT</literal> property
!      supported by some other databases). In the current
!      implementation, specifying
  
  <programlisting>
  CREATE TABLE <replaceable class="parameter">tablename</replaceable> (
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*** 684,715 ****
      </para>
  
      <para>
       The type names <type>serial</type> and <type>serial4</type> are
       equivalent: both create <type>integer</type> columns.  The type
       names <type>bigserial</type> and <type>serial8</type> work just
       the same way, except that they create a <type>bigint</type>
       column.  <type>bigserial</type> should be used if you anticipate
!      the use of more than 2<superscript>31</> identifiers over the lifetime of the table.
      </para>
  
      <para>
!      The sequence created by a <type>serial</type> type is automatically
!      dropped when
!      the owning column is dropped, and cannot be dropped otherwise.
!      (This was not true in <productname>PostgreSQL</productname> releases
!      before 7.3.  Note that this automatic drop linkage will not occur for a
!      sequence created by reloading a dump from a pre-7.3 database; the dump
!      file does not contain the information needed to establish the dependency
!      link.)
      </para>
  
!     <note><para>
!      Prior to <productname>PostgreSQL</productname> 7.3, <type>serial</type>
!      implied <literal>UNIQUE</literal>.  This is no longer automatic.  If
!      you wish a serial column to be <literal>UNIQUE</literal> or a 
!      <literal>PRIMARY KEY</literal> it must now be specified, same as with
!      any other data type.
!     </para></note>
     </sect2>
    </sect1>
  
--- 685,733 ----
      </para>
  
      <para>
+      To use a <type>serial</type> column to insert the next value of
+      the sequence into the table, specify that the <type>serial</type>
+      column should be assigned the default value. This can be done
+      either be excluding from the column from the list of columns in
+      the <command>INSERT</command> statement, or through the use of
+      the <literal>DEFAULT</literal> keyword.
+     </para>
+ 
+     <para>
       The type names <type>serial</type> and <type>serial4</type> are
       equivalent: both create <type>integer</type> columns.  The type
       names <type>bigserial</type> and <type>serial8</type> work just
       the same way, except that they create a <type>bigint</type>
       column.  <type>bigserial</type> should be used if you anticipate
!      the use of more than 2<superscript>31</> identifiers over the
!      lifetime of the table.
      </para>
  
      <para>
!      The sequence created by a <type>serial</type> type is
!      automatically dropped when the owning column is dropped, and
!      cannot be dropped otherwise.  (This was not true in
!      <productname>PostgreSQL</productname> releases before 7.3.  Note
!      that this automatic drop linkage will not occur for a sequence
!      created by reloading a dump from a pre-7.3 database; the dump
!      file does not contain the information needed to establish the
!      dependency link.) Furthermore, this dependency between sequence
!      and column is made only for the <type>serial</> column itself; if
!      any other columns reference the sequence (perhaps by manually
!      calling the <function>nextval()</>) function), they may be broken
!      if the sequence is removed. Using <type>serial</> columns in
!      fashion is considered bad form.
      </para>
  
!     <note>
!      <para>
!       Prior to <productname>PostgreSQL</> 7.3, <type>serial</type>
!       implied <literal>UNIQUE</literal>.  This is no longer automatic.
!       If you wish a serial column to be <literal>UNIQUE</literal> or a
!       <literal>PRIMARY KEY</literal> it must now be specified, just as
!       with any other data type.
!      </para>
!     </note>
     </sect2>
    </sect1>