-----Original Message----- From: Mike Christensen [mailto:mike@xxxxxxxxxxxxx] Sent: Thursday, June 16, 2011 1:05 AM To: pgsql-general@xxxxxxxxxxxxxx Subject: Constraint to ensure value does NOT exist in another table? I know I can setup a FK constraint to make sure Table1.ColA exists in Table2.Key, however what if I want to do the reverse? I want to ensure Table1.ColA does NOT exist in Table2.Key.. Can I do this with any sort of CHECK constraint, trigger, custom function, etc? Thanks! Mike Trigger (with corresponding trigger function) will definitely do the job. Regards, Igor Neyman -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
