On Tue, 28 Jan 2003, Rodger Donaldson wrote: > Now, adding a UNIQUE constraint on the pk for add_queue weeds out > dupes there. However, attempting to add a cross-table UNIQUE check > with: > > alter table add_queue add constraint add_queue_no_dupe_sites unique > (sites.url); > ERROR: parser: parse error at or near "." > > ,,,fails. Foreign key constraints will only require a match (of one > sort or another) in the foreign table, according to the postgresql 7.2 > documentation, and do not have an option to require no match. > > Am I missing something obvious (syntax for UNIQUE, for example), or > trying to do something that just doesn't work that way?
I'm not sure what a unique constraint on sites.url on table add_queue is supposed to mean precisely. You can probably come pretty close by making a set of triggers on both tables however. ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
