>I thought that an neforced unique key was just that... an enforced unique >key. Can anyone clear this up for me? > >I guess its a bit like driving a car. You *could* drive on the other side >of the road if you wanted to, even though you know you shouldn't. > >I see Primary/Candidate indexes in rahter the same way - there are things >you *CAN* do, but it doesn't mean you should do them. OTOH, PK for !deleted() should not be allowed nor made possible ever. It allows for creating a record with a key which is equal to a key of a deleted record, so we don't have problem of keys which appear to appear nowhere in the table but are impossible to use, because some deleted record keeps it. But then, we have the opposite problem: what will happen if we try the Recall the deleted record? We'd have the same PK violation again, and we probably would have to either drop the key or forget about the deleted record.