Re: foreign key constraint versus referential integrity constraint

> I prefer the term "inclusion dependency": projection of one relation
> (that is rvRedemptions v [CouponID]) is a supepersetset of projection
> of the other (i.e. rvOrders v [CouponID]). I thought that all three
> terms are the same; perhaps with foreign key constraint adding some
> insignificant matter, like the "smaller" set being unique.

BTW, one limitation of foreign keys which I find particularly annoying is that they only work when we're talking about base tables whereas I've already bumped a few times into a situation where I would have liked to constrain (on) the contents of a view. That sometimes happens when you have to go beyond 3NF or you're working with a conceptual model which allows multiple inheritance and/or union types. Do you happen to know whether this sort of thing is formally covered by the concept of inclusion dependency?

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Sampo