> I am trying to create a unique constraint for a typed datatable for
> multiple columns so the same group of values will not appear more than
> once for any one row (I can't make this group of columns a composite
> primary key as one of the columns can sometimes be null). If I was
> creating a non-typed dataset, then in the code it is quite simple to
> implement this:
>
> Dim dt As New DataTable("MyTable")
>
>  -- CODE TO DEFINE TABLE HERE ---
>
> Dim myUniqueConstraint As UniqueConstraint
> myUniqueConstraint = New UniqueConstraint(New DataColumn()
> {dt.Columns("column1"), dt.Columns("column2"), dt.Columns("column3"),
> dt.Columns("column4")})
> dt.Constraints.Add(myUniqueConstraint)
>
> However, I don't see how to do this for a typed dataset. I can select
> all of the columns that I want in the dataset designer for the
> datatable and assign the "unique" property to true, but the code that
> it generates is individual unique constraints for each of the columns,
> not a composite for all columns. Is there a way to set this in the
> designer? Perhaps I can add the code in the partial class of the
> dataset (I don't know how to do this...suggestions?). Is this possible
> at all, or do I have to change my typed dataset, which only contains
> one table, back into an untyped dataset?
>
> Thanks,
> Marcus