On Tue, 18 Jan 2005 11:27:49 -0800, Jacques Kilchoer <Jacques.Kilchoer@xxxxxxxxx> wrote: > The Oracle optimizer might view a PK constraint differently than a > unique constraint on not null columns, one of the performance experts on > the list could probably say a word or two about that. http://www.dbazine.com/jlewis21.shtml Jonathan does not mention the optimizer, though it appears from the article that the CBO may consider a UK with NOT NULL as identical to a PK. -- Jared Still Certifiable Oracle DBA and Part Time Perl Evangelist -- //www.freelists.org/webpage/oracle-l