On Fri, 2002-09-13 at 04:27, Christopher Kings-Lynne wrote: > > AFAIK, the extra index only slows down my inserts - it basically contains > > no usable information... > > Not 100% true. It will speed up cascade delete and update... > > > shouldn't the presence of _primary_key_ in > > multicol foreign key be enough to decide whether the whole key is unique > > or not? > > Hmmm - thinking about it, I don't see why postgres would need the entire > thing to be unique...can't think of a reason at the moment. Stephen?
If it's not all unique, you cannot be guaranteed there is a single row with those values in the referenced table. -- Rod Taylor ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org
