 <p>You may create a trigger like this: on updating dbo.Parts table update dbo.part_numbers table and vice versa. Here is a MSDN article about triggers: <a href="http://msdn.microsoft.com/en-us/library/ms189799.aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/ms189799.aspx</a></p>