From: Tom Lane Date: Fri, 6 Aug 2010 18:55:24 +0000 (+0000) Subject: Fix inaccurate description of deferrable unique constraints, per Dean Rasheed. X-Git-Tag: REL9_1_ALPHA1~117 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a209b9850f0c3bec3ae1a4b1565621c5d8354710;p=postgresql Fix inaccurate description of deferrable unique constraints, per Dean Rasheed. --- diff --git a/doc/src/sgml/release-9.0.sgml b/doc/src/sgml/release-9.0.sgml index 2ab27b721e..ddd0acc2e9 100644 --- a/doc/src/sgml/release-9.0.sgml +++ b/doc/src/sgml/release-9.0.sgml @@ -1,4 +1,4 @@ - + Release 9.0 @@ -91,7 +91,8 @@ Deferrable - unique constraints, now permit mass updates to unique keys. + unique constraints. Mass updates to unique keys are now possible + without trickery. @@ -1122,10 +1123,13 @@ - This allows UPDATE tab SET col = col + 1 to work on - columns that have a unique indexes or are marked as primary key, - but DEFERRABLE INITIALLY DEFERRED must be used to mark - the constraint as deferred. + This allows 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 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.