>With the combined COVERAGE table, the OFF staff fits RI, but the ON staff fits a business rule that does not translate well into RI (at least as it relates to DELETE action). I think you understand it well enough to know that the 3 choices won't work here. Well, actually, the ON staff does fit the ignore option for RI, as long as you handle setting null some other way.

Hi David. I think this problem will still exist since I would need a link between the two coverage table and neither rule fits there either. You have given me food for thought though.