> I am going to assume that by binary you mean boolean. If so it already has > three states NULL,True,False. Uh, not really, no. NULL indicates the absence or indeterminacy of a state, and has a number of properties that make it unsuitable for representing anything other than that. Use an enum. -- Regards, Peter Geoghegan -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general