Re: functional dependencies

Dear Marshall,
  I did not understand your example of trivial FD's. Please could you explain it more clearly and in tabular form if possible.

Regards,
Rohan.

"Marshall Spight" <mspight_at_dnai.com> wrote in message news:<8k1Ha.1005196$Zo.227474_at_sccrnsc03>...
> "Rohan Hathiwala" <rp_hathiwala_at_yahoo.com> wrote in message news:3ec1cded.0306102221.2d9b2852_at_posting.google.com...
> >
> > I would also like to post another question at this point.
> > Can any one give me an example of a relation where we have a
> > trivial FD?
> > A trivial FD is of the form
> > A -> B where B is a subset of A.
>
> Sure. Let's say we have a table of unique integers Z. For fun, let's say
> it contains three rows: Z = 1, Z = 2, and Z = 3.
>
> Now A, B are sets of columns. Here, A = {Z}, and B = {Z}.
> B is functionally dependent on A. B is a subset of A. Easy.
>
>
> Marshall
Received on Mon Jun 16 2003 - 07:50:11 CEST