Maybe what author means is that from the db design standpoint, composite keys are used much less often than they could be. Very often unique table row can be de

Maybe what author means is that from the db design standpoint, composite keys are used much less often than they could be. Very often unique table row can be defined by some other column or a pair, on which you will probably put an index anyway. But that's just playing devil's advocate. In general I think ids are fine because ORMs play nice with them and FKs are simple.