From 8f60f43f2e23add472acd988741411e025bff87d Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 2 Sep 2002 20:04:40 +0000
Subject: Department of second thoughts: make checks for replacing a view
 slightly more flexible, and improve the error reporting.  Also, add
 documentation for REPLACE RULE/VIEW.

---
 doc/src/sgml/ref/create_rule.sgml | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

(limited to 'doc/src/sgml/ref/create_rule.sgml')

diff --git a/doc/src/sgml/ref/create_rule.sgml b/doc/src/sgml/ref/create_rule.sgml
index 86046359b4..998d075a64 100644
--- a/doc/src/sgml/ref/create_rule.sgml
+++ b/doc/src/sgml/ref/create_rule.sgml
@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_rule.sgml,v 1.36 2002/05/18 15:44:47 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_rule.sgml,v 1.37 2002/09/02 20:04:39 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -21,17 +21,15 @@ PostgreSQL documentation
    <date>2001-01-05</date>
   </refsynopsisdivinfo>
   <synopsis>
-CREATE RULE <replaceable class="parameter">name</replaceable> AS ON <replaceable class="parameter">event</replaceable>
+CREATE [ OR REPLACE ] RULE <replaceable class="parameter">name</replaceable> AS ON <replaceable class="parameter">event</replaceable>
     TO <replaceable class="parameter">table</replaceable> [ WHERE <replaceable class="parameter">condition</replaceable> ]
     DO [ INSTEAD ] <replaceable class="parameter">action</replaceable>
 
 where <replaceable class="PARAMETER">action</replaceable> can be:
 
 NOTHING
-|
-<replaceable class="parameter">query</replaceable>
-|
-( <replaceable class="parameter">query</replaceable> ; <replaceable class="parameter">query</replaceable> ... )
+| <replaceable class="parameter">query</replaceable>
+| ( <replaceable class="parameter">query</replaceable> ; <replaceable class="parameter">query</replaceable> ... )
   </synopsis>
 
   <refsect2 id="R2-SQL-CREATERULE-1">
@@ -76,9 +74,10 @@ NOTHING
       <term><replaceable class="parameter">condition</replaceable></term>
       <listitem>
        <para>
-	Any SQL conditional expression (returning <type>boolean</type>).  The condition expression may not
+	Any SQL conditional expression (returning <type>boolean</type>).
+	The condition expression may not
 	refer to any tables except <literal>new</literal> and
-	<literal>old</literal>.
+	<literal>old</literal>, and may not contain aggregate functions.
        </para>
       </listitem>
      </varlistentry>
@@ -142,6 +141,14 @@ CREATE RULE
    Description
   </title>
 
+  <para>
+   <command>CREATE RULE</command> defines a new rule applying to a specified
+   table or view.
+   <command>CREATE OR REPLACE RULE</command> will either create a
+   new rule, or replace an existing rule of the same name for the same
+   table.
+  </para>
+
   <para>
    The <productname>PostgreSQL</productname> 
    <firstterm>rule system</firstterm> allows one to define an
@@ -318,7 +325,7 @@ UPDATE mytable SET name = 'foo' WHERE id = 42;
    </title>
 
    <para>
-    <command>CREATE RULE</command> statement is a <productname>PostgreSQL</productname>
+    <command>CREATE RULE</command> is a <productname>PostgreSQL</productname>
     language extension.
     There is no <command>CREATE RULE</command> statement in <acronym>SQL92</acronym>.
    </para>
-- 
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