Using ADO.NET 2.0, added a unique constraint, but not primary key.
I am able to merge in data which violates constraint and then get an exception.
But the damage is done and the unique column has multiple rows with same value.
Also, I can add a new row and violate the unique column constraint.
This does not make sense to me. Am I missing something? If not, what is the purpose of unique constraint, and what exactly, does it constrain?