Hi everybody, i'd like to know if it is better to use a primary key made of a couple columns, than to use a constraint UNIQUE() on this couple columns, regarding the sake of postgresql. For example, i've got these two tables, 'buyer' and 'purchaser' and i want to make an association table buyer_purchaser in which i get only some couples (id_buyer, id_purchaser), with a unique() contraint on them. If i put a primary key on the couple, i won't use it, because the framework on top of it is unable to use a primary key made of a couple of columns. Si my question is : is it better, in so far as only the database is concerned, to have a primary key than a unique() contraint on a couple columns ? Thanks in advance for your answers, 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
