"Kynn Jones" <kynnjo@xxxxxxxxx> writes: > In short, my question is: is there a way to designate a pre-existing > UNIQUE INDEX (based on data contained in NOT NULL fields) as the basis > for a table's PRIMARY KEY? No. If there were, that client software you mention would very likely still get confused. Both the SQL standard and a lot of code assume that the constituents of a PRIMARY KEY are just-plain-columns. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq