Fix pg_dump to dump serial columns as serials. Per pghackers discussion,

cause SERIAL column declaration not to imply UNIQUE, so that this can be
done without creating an extra index.

Author: tglsfdc

doc/src/sgml/datatype.sgml

@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.98 2002/08/13 20:40:43 momjian Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/datatype.sgml,v 1.99 2002/08/19 19:33:33 tgl Exp $
 -->
 
  <chapter id="datatype">
@@ -665,14 +665,17 @@ CREATE TABLE <replaceable class="parameter">tablename</replaceable> (
 <programlisting>
 CREATE SEQUENCE <replaceable class="parameter">tablename</replaceable>_<replaceable class="parameter">colname</replaceable>_seq;
 CREATE TABLE <replaceable class="parameter">tablename</replaceable> (
-    <replaceable class="parameter">colname</replaceable> integer DEFAULT nextval('<replaceable class="parameter">tablename</replaceable>_<replaceable class="parameter">colname</replaceable>_seq') UNIQUE NOT NULL
+    <replaceable class="parameter">colname</replaceable> integer DEFAULT nextval('<replaceable class="parameter">tablename</replaceable>_<replaceable class="parameter">colname</replaceable>_seq') NOT NULL
 );
 </programlisting>
 
      Thus, we have created an integer column and arranged for its default
-     values to be assigned from a sequence generator.  UNIQUE and NOT NULL
-     constraints are applied to ensure that explicitly-inserted values
-     will never be duplicates, either.
+     values to be assigned from a sequence generator.  A <literal>NOT NULL</>
+     constraint is applied to ensure that a NULL value cannot be explicitly
+     inserted, either.  In most cases you would also want to attach a
+     <literal>UNIQUE</> or <literal>PRIMARY KEY</> constraint to prevent
+     duplicate values from being inserted by accident, but this is
+     not automatic.
     </para>
 
     <para>
@@ -685,20 +688,23 @@ CREATE TABLE <replaceable class="parameter">tablename</replaceable> (
     </para>
 
     <para>
-     Implicit sequences supporting the <type>serial</type> types are
-     not automatically dropped when a table containing a serial type
-     is dropped. So, the following commands executed in order will likely fail:
-
-<programlisting>
-CREATE TABLE <replaceable class="parameter">tablename</replaceable> (<replaceable class="parameter">colname</replaceable> SERIAL);
-DROP TABLE <replaceable class="parameter">tablename</replaceable>;
-CREATE TABLE <replaceable class="parameter">tablename</replaceable> (<replaceable class="parameter">colname</replaceable> SERIAL);
-</programlisting>
-
-     The sequence will remain in the database until explicitly dropped using
-     <command>DROP SEQUENCE</command>.  (This annoyance will probably be
-     fixed in some future release.)
+     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 datatype.
+    </para></note>
    </sect2>
   </sect1>
 

doc/src/sgml/release.sgml

@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.147 2002/08/18 09:36:25 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/release.sgml,v 1.148 2002/08/19 19:33:34 tgl Exp $
 -->
 
 <appendix id="release">
@@ -24,6 +24,7 @@ CDATA means the content is "SGML-free", so you can write without
 worries about funny characters.
 -->
 <literallayout><![CDATA[
+SERIAL no longer implies UNIQUE; specify explicitly if index is wanted
 pg_dump -n and -N options have been removed.  The new behavior is like -n but knows about key words.
 CLUSTER is no longer hazardous to your schema
 COPY accepts a list of columns to copy

src/backend/parser/analyze.c

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.241 2002/08/19 15:08:47 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.242 2002/08/19 19:33:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -876,11 +876,6 @@ transformColumnDefinition(ParseState *pstate, CreateStmtContext *cxt,
 		constraint->keys = NIL;
 		column->constraints = lappend(column->constraints, constraint);
 
-		constraint = makeNode(Constraint);
-		constraint->contype = CONSTR_UNIQUE;
-		constraint->name = NULL;	/* assign later */
-		column->constraints = lappend(column->constraints, constraint);
-
 		constraint = makeNode(Constraint);
 		constraint->contype = CONSTR_NOTNULL;
 		column->constraints = lappend(column->constraints, constraint);
@@ -1209,10 +1204,9 @@ transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
 
 	/*
 	 * Scan the index list and remove any redundant index specifications.
-	 * This can happen if, for instance, the user writes SERIAL PRIMARY
-	 * KEY or SERIAL UNIQUE.  A strict reading of SQL92 would suggest
-	 * raising an error instead, but that strikes me as too
-	 * anal-retentive. - tgl 2001-02-14
+	 * This can happen if, for instance, the user writes UNIQUE PRIMARY KEY.
+	 * A strict reading of SQL92 would suggest raising an error instead,
+	 * but that strikes me as too anal-retentive. - tgl 2001-02-14
 	 *
 	 * XXX in ALTER TABLE case, it'd be nice to look for duplicate
 	 * pre-existing indexes, too.
@@ -1262,7 +1256,7 @@ transformIndexConstraints(ParseState *pstate, CreateStmtContext *cxt)
 
 	/*
 	 * Finally, select unique names for all not-previously-named indices,
-	 * and display WARNING messages.
+	 * and display NOTICE messages.
 	 *
 	 * XXX in ALTER TABLE case, we fail to consider name collisions against
 	 * pre-existing indexes.