Re: Transitive dependencies

"Jan Hidders" <jan.hidders_at_REMOVETHIS.pandora.be> wrote in message news:jdEgb.63737$B_3.2973734_at_phobos.telenet-ops.be...
> > I see the award relation functional dependencies as follows:
> >
> > FD1 (institute, year) -> research, research_err, support, support_err
> > FD2 research -> research_err
> > FD3 support -> support_err
>
> I don't think FD2 and FD3 are correct. Think about it. Does every row
> with the same amount in the research column have the same error in the
> research_err column? I don't think so. As far as I can tell these
> columns properly depend upon (institute, year) so unless you include the
> error descriptions in your table it is in 3NF (and very probably in 5NF).
>
> -- Jan Hidders

You are quite right Jan the _err attributes do depend on (institute, year) and the FD: institute, year, research -> research_err does not hold either.

Thank you for the clarification and taking the time to respond.

Regards,
Mark Received on Tue Oct 07 2003 - 22:05:50 CEST