From a209b9850f0c3bec3ae1a4b1565621c5d8354710 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 6 Aug 2010 18:55:24 +0000
Subject: [PATCH] Fix inaccurate description of deferrable unique constraints,
per Dean Rasheed.
---
doc/src/sgml/release-9.0.sgml | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/doc/src/sgml/release-9.0.sgml b/doc/src/sgml/release-9.0.sgml
index 2ab27b721ea..ddd0acc2e90 100644
--- a/doc/src/sgml/release-9.0.sgml
+++ b/doc/src/sgml/release-9.0.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/release-9.0.sgml,v 2.45 2010/08/06 17:56:43 rhaas Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/release-9.0.sgml,v 2.46 2010/08/06 18:55:24 tgl Exp $ -->
<sect1 id="release-9-0">
<title>Release 9.0</title>
@@ -91,7 +91,8 @@
<listitem>
<para>
<link linkend="SQL-CREATETABLE-compatibility">Deferrable
- unique constraints, now permit mass updates to unique keys.</link>
+ unique constraints. Mass updates to unique keys are now possible
+ without trickery.</link>
</para>
</listitem>
@@ -1122,10 +1123,13 @@
</para>
<para>
- This allows <command>UPDATE tab SET col = col + 1</> to work on
- columns that have a unique indexes or are marked as primary key,
- but <literal>DEFERRABLE INITIALLY DEFERRED</> must be used to mark
- the constraint as deferred.
+ This allows <command>UPDATE tab SET col = col + 1</> to work reliably
+ on columns that have unique indexes or are marked as primary keys.
+ If the constraint is specified as <literal>DEFERRABLE</> it will be
+ checked at the end of the statement, rather than after each row is
+ updated. The constraint check may also be deferred until the end of the
+ current transaction, allowing updates to be spread over multiple SQL
+ commands.
</para>
</listitem>
--
GitLab