Sure it does. You need to ensure that you only have one non-invalidated record. If you don't have partial unique index, you can't guarantee that two concurren

Sure it does. You need to ensure that you only have one non-invalidated record. If you don't have partial unique index, you can't guarantee that two concurrent transactions won't invalidate the same row and add two different rows. With a partial unique index, you can make that guarantee.