Hi. Hope I'm articulating the question correctly. I currently have a foreign key like this: "fk_table2" FOREIGN KEY (id) REFERENCES table1(id) ON DELETE CASCADE; Given the peculiar needs of this db, it seems that in some cases we will need to track the "id" of table2 against a concatenation of two columns in table2. So in pseudocode, it would look something like this. "fk_table2" FOREIGN KEY (id) REFERENCES table1(id OR id||'.'||column2) ON DELETE CASCADE; Do I need a separate constraint for this? Many thanks for any pointers! -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general