On 23/04/10 15:50, Adrian von Bidder wrote:
On Friday 23 April 2010 03.27:29 Craig Ringer wrote:insert into test (a,b) values ('fred',NULL); insert into test (a,b) values ('fred',NULL); ... and will succeed:Hmm. Perhaps not as ugly as "none" placeholders: create unique index on test (b) where a is null; create unique index on test (a) where b is null;
True ... and Pg can even use them both together for bitmap index scans, albeit not as efficiently as a single multicolumn index.
This really isn't viable for >2 nullable fields, though, as the number of indexes increases to impractical levels rather quickly.
-- Craig Ringer -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
