Database Design - Supertypes and Subtypes

[brianbarenbaum]

I'm designing a database and I'm not sure if the way I'm doing it is best.

I attached a jpg of the design to another forum. Please take a look here:

http://www.daniweb.com/techtalkforums/thread42358.html

I'm most concerned with the subtype relationships (Datasets to production datasets, Datasets to delivery_datasets, etc…). I’ve created a database with the design in the diagram and it seems like some queries are more difficult to write than they should be. Would anyone mind taking a look at the design and letting me know if I’m on the right track.

Thanks in advance!