Re: How can I proove associtivity of natural in relational algebra?

Mikito Harakiri wrote:
> Filter911 wrote:
> > Can someone give me a link for a full proof or something?
>
> Given relations A,B, and C, expand each realtion into a (possibly
> infinite) relations A', B', and C' with the same set of attributes
> (which is the union of the attribute sets for A, B, and C). Then, the
> join of A, B and C is the intersection of A', B', and C'. Intersection
> is associative.

What do you mean by "expand each relation"?

Thanks Received on Mon Nov 21 2005 - 22:22:57 CET