SQL Server UNIQUE constraint

[panayotisk]

Hi,
I want to create a constraint on a field.
I need uniqueness as long as the field is not null (allow multiple nulls).
How am I going to do this?

[hspc]

I believe you can't..
you can create a triggers to handle this setuation..
one trigger for insert and the other for update.And check if the data violates your rules.

[panayotisk]

Yes, it is true. The problem I'm having now is actually make this trigger work since I need to use dynamic SQL. I posted this in another thread.

Thanx a lot

Panayotis