Re: Foreign superkey support

paul c wrote:
> Marshall wrote:
> > paul c wrote:
> >> Perhaps all I'm saying is that the basic relational algebra doesn't need
> >> a foreign key concept which I admit is a deviation from the specific
> >> question.
> >
> > I don't think of constraints as being part of the algebra per se.
> > ...
>
> If they aren't, I think that would mean the algebra is incomplete (and
> every relation's value could only get 'larger', until it reached the
> product of its domains' values which could then never be 'constrained'
> to a smaller set).

Well, it depends on your meaning of "complete." If I understand you correctly, you are saying that the algebra by itself is not a complete solution for data management; I would have to agree. The algebra (by iteslf) doesn't let you manipulate or constrain; it has no insert or delete, for example.

Marshall Received on Wed Aug 09 2006 - 07:17:28 CEST