True enough, Tom, and apologies for being entirely too brief on my previous response. You can limit the BIT "field" (cough, cough, gasp! 🙂 )by adding a NOT NULL constraint, as you say. I just wanted to make sure that newbies that might read this understand that doesn't change the fact that there is no Yes/No only data type in SQL Server nor will it change the fact that, nothing else provided, the BIT data type can be NULL.
--Jeff Moden
Change is inevitable... Change for the better is not.