Re: Question re: Practical Issues in Database Management

On 22 mrt, 22:03, Joe Thurbon <use..._at_thurbon.com> wrote:
> Carlos M. Calvelo wrote:
> > On 22 mrt, 00:49, Joe Thurbon <use..._at_thurbon.com> wrote:
> >> I've had a look on the dbdebunk website, but errata are only available
> >> via email. As far as I'm aware, the site is no longer kept active.
>
> >> Does anyone know if the errata are available through another means?
>
> > Another (different!) errata at
> >http://www.dbdebunk.com/page/page/668187.htm
>
> > The two lists seem to overlap.
>
> Hmm, an update anomaly?

:)
I see some redundancy, that's for sure!

>
> Thanks Carlos.
>
> To all:
>
> It seems to me that neither of the errata I've been pointed to address
> the issue that I originally mentioned in this thread. Namely, that the
> definitions of multivalued dependencies and 4th normal form given in the
> book seem to be overly strict.
>
> In particular, if a multivalued dependancy is defined as:
>
> "A MVD between two columns exists when sets of values in one column are
> each associated with values in another column"

Maybe it should read:
"A MVD between two columns exists when sets of values in one column are
each associated with values in another column independently of values in a *third* column"

So, in figure 5.8 A
EMP# ->> PROJ independently of ACT and
EMP# ->> ACT independently of PROJ.

[snip]

>
> Have I found an error in the book (unlikely).

Maybe you did. Anyone?

Regards,
Carlos Received on Fri Mar 23 2007 - 00:46:32 CET