Re: 3NF but not BCNF

The explanation would be greatly appreciated by your professor if you thought it through and came up with it yourself.

"Phil Cook" <pacookSPAM_IRIS_at_blueyonder.co.uk> wrote in message news:Ff7M6.8074$zq2.600444_at_news1.cableinet.net...
> I am presented with the following question:
>
> Argue that if a relation schema R is in Third Normal Form but not in
> Boyce-Codd
> Normal Form with respect to a set of functional dependencies F, then
 it
> must have
> at least two distinct keys for R with respect to F which overlap, i.e.
> such that their
> intersection is nonempty.
>
> Unfortunately, my textbook only mentions this point in passing, referring
 to
> some paper by Vincent and Srinivasan. This paper does not appear to be
> available online, however.
>
> Any explanation would be greatly appreciated.
>
>
Received on Tue May 15 2001 - 15:58:34 CEST