>I don't think that any SQL Server setting can resolve the problem because it's on .NET side. Google on '.net Failed to enable constraints'

When I did that search on Google, because this is so generic, I ended up with way too much situations here and none of those I have seen seem to relate to the situation I had. The only think I could see if that, if on the .NET side, the VFPOleDB provider would allow that SQL to be executed but not the SQLClient provider.