Steve,

The DataColumn class has a property AllowDBNull which addresses the non-null question. Also, you can use the Expression property in a calculated column to place conditional constraints for individual rows, or for all of the rows.

>It seems from the docs that there are only two types of constraints - uniqueness/PK constraints and FK constraints. Is this the case - we can't create constraints requiring non-null, non-empty values, values greater than a certain amount, etc.?
>
>The docs *imply* that you can create constraints that, for instance, require the sum of a column in a DataTable must equal a specific value, but I can't seem to figure out how this is done, or if it's even possible to do this through a constraint.
>
>Thanks.