How do I enforce data integrity rules in my database?

Question

I\'m designing this collection of classes and abstract (MustInherit) classes…

Answer 1

SQL Server doesn't know anything about your classes. I think that you'll have to enforce this by using a Factory class that constructs/deconstructs all these for you and makes sure that you're passing the right values depending upon the type.

Technically this is not "enforcing the rules in the database" but I don't think that this can be done in a single table. Fields either accept nulls or they don't.

Another idea could be to explore SQL Functions and Stored Procedures that do the same thing. BUt you cannot enforce a field to be NOT NULL for one record and NULL for the next one. That's your Business Layer / Factory job.