> Just for the sake of completeness, there are exactly two differences: > * PRIMARY KEY implies NOT NULL on the key columns; UNIQUE doesn't. > * PRIMARY KEY creates a default target for foreign key references, > ie, if you've declared a primary key then you can later just say > "REFERENCES mytab" instead of spelling out "REFERENCES mytab(keycol)". > So "UNIQUE + NOT NULL" is pretty dang close to the same as "PRIMARY > KEY", but not quite. > regards, tom lane Thanks too, Tom :-) Best regards, David -- David Pradier -- Directeur Technique de Clarisys Informatique -- Chef de projet logiciels libres / open-source ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
