diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2010-08-06 18:55:30 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2010-08-06 18:55:30 +0000 |
| commit | 9a299eee03a509488ef25cf7b2330f51c0638500 (patch) | |
| tree | c28e8f9180752be1a82771819359560c01ff7053 | |
| parent | 00d9d5964eb2c5ce2f22836524beb9631f3c064a (diff) | |
Fix inaccurate description of deferrable unique constraints, per Dean Rasheed.
| -rw-r--r-- | doc/src/sgml/release-9.0.sgml | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/doc/src/sgml/release-9.0.sgml b/doc/src/sgml/release-9.0.sgml index d9467fd89f7..b7ce612cac7 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 2.39.2.3 2010/08/06 17:57:03 rhaas Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/release-9.0.sgml,v 2.39.2.4 2010/08/06 18:55:30 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> |