On Fri, Jun 30, 2006 at 16:41:57 +0200, Alex Soto <alex.soto@xxxxxxxxxxx> wrote: > I am is Alex, and I m developing a product with PostgreSQL 8.1. I have a > problem. This problem is that i have some unique constraints with > multi-columns. The problem is that there is some that of the check > constraint condition that can be null. As it is described in section > 5.3.3, null of one row is different from the null of other row, so we > can have two entries with same values inserted because of null value is > not a considered equal in this comparison. > > Is there any administration syntax to change this behavior so null > values are treated as same value? No, but you can use partial indexes to impose that constraint. This came up a couple of months ago on one of the lists and there was a bit more discussion on the specifics if "use partial indexes" isn't enough of a hint for you.
