troubleshooting Question dataset unique constraint does not prevent adding/merging rows which violate unique constraint

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brotherbill999 asked on
.NET ProgrammingC#Visual Basic.NET
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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?
Daniel Junges

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