Fix all known problems with pg_dump's handling of serial sequences

by abandoning the idea that it should say SERIAL in the dump.  Instead,
dump serial sequences and column defaults just like regular ones.
Add a new backend command ALTER SEQUENCE OWNED BY to let pg_dump recreate
the sequence-to-column dependency that was formerly created "behind the
scenes" by SERIAL.  This restores SERIAL to being truly "just a macro"
consisting of component operations that can be stated explicitly in SQL.
Furthermore, the new command allows sequence ownership to be reassigned,
so that old mistakes can be cleaned up.

Also, downgrade the OWNED-BY dependency from INTERNAL to AUTO, since there
is no longer any very compelling argument why the sequence couldn't be
dropped while keeping the column.  (This forces initdb, to be sure the
right kinds of dependencies are in there.)

Along the way, add checks to prevent ALTER OWNER or SET SCHEMA on an
owned sequence; you can now only do this indirectly by changing the
owning table's owner or schema.  This is an oversight in previous
releases, but probably not worth back-patching.

1 files changed, 47 insertions, 3 deletions

diff --git a/doc/src/sgml/ref/create_sequence.sgml b/doc/src/sgml/ref/create_sequence.sgml
index 7a094f6ef23..5fa16c2a81c 100644
--- a/doc/src/sgml/ref/create_sequence.sgml
+++ b/doc/src/sgml/ref/create_sequence.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/create_sequence.sgml,v 1.43 2005/11/01 21:09:50 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/create_sequence.sgml,v 1.44 2006/08/21 00:57:24 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -23,6 +23,7 @@ PostgreSQL documentation
 CREATE [ TEMPORARY | TEMP ] SEQUENCE <replaceable class="parameter">name</replaceable> [ INCREMENT [ BY ] <replaceable class="parameter">increment</replaceable> ]
     [ MINVALUE <replaceable class="parameter">minvalue</replaceable> | NO MINVALUE ] [ MAXVALUE <replaceable class="parameter">maxvalue</replaceable> | NO MAXVALUE ]
     [ START [ WITH ] <replaceable class="parameter">start</replaceable> ] [ CACHE <replaceable class="parameter">cache</replaceable> ] [ [ NO ] CYCLE ]
+    [ OWNED BY { <replaceable class="parameter">table</replaceable>.<replaceable class="parameter">column</replaceable> | NONE } ]
 </synopsis>
  </refsynopsisdiv>
 
@@ -193,6 +194,22 @@ SELECT * FROM <replaceable>name</replaceable>;
      </para>
     </listitem>
    </varlistentry>
+
+   <varlistentry>
+    <term><literal>OWNED BY</literal> <replaceable class="parameter">table</replaceable>.<replaceable class="parameter">column</replaceable></term>
+    <term><literal>OWNED BY NONE</literal></term>
+    <listitem>
+     <para>
+      The <literal>OWNED BY</literal> option causes the sequence to be
+      associated with a specific table column, such that if that column
+      (or its whole table) is dropped, the sequence will be automatically
+      dropped as well.  The specified table must have the same owner and be in
+      the same schema as the sequence.
+      <literal>OWNED BY NONE</literal>, the default, specifies that there
+      is no such association.
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
  </refsect1>
 
@@ -300,11 +317,38 @@ END;
    <command>CREATE SEQUENCE</command> conforms to the <acronym>SQL</acronym>
    standard, with the following exceptions:
    <itemizedlist>
-    <listitem><para>The standard's <literal>AS &lt;data type&gt;</literal> expression is not supported.</para></listitem>
-    <listitem><para>Obtaining the next value is done using the <function>nextval()</> function instead of the standard's <command>NEXT VALUE FOR</command> expression.</para></listitem>
+    <listitem>
+     <para>
+      The standard's <literal>AS &lt;data type&gt;</literal> expression is not
+      supported.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Obtaining the next value is done using the <function>nextval()</>
+      function instead of the standard's <command>NEXT VALUE FOR</command>
+      expression.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      The <literal>OWNED BY</> clause is a <productname>PostgreSQL</>
+      extension. 
+     </para>
+    </listitem>
    </itemizedlist>
   </para>
  </refsect1>
+
+ <refsect1>
+  <title>See Also</title>
+
+  <simplelist type="inline">
+   <member><xref linkend="sql-altersequence" endterm="sql-altersequence-title"></member>
+   <member><xref linkend="sql-dropsequence" endterm="sql-dropsequence-title"></member>
+  </simplelist>
+ </refsect1>
+
 </refentry>
 
 <!-- Keep this comment at the end of the file