Re: Little design mistakes that can be easily avoided (2): Listenning to CELKO (and CELKO alikes)

On May 28, 9:16 pm, "Brian Selzer" <b..._at_selzer-software.com> wrote:
> "Gene Wirchenko" <g..._at_ocis.net> wrote in message
>
> news:cc0m53lkdf0os673kfdunubc46dkidq1uo_at_4ax.com...
>
> > Jon Heggland <jon.heggl..._at_idi.ntnu.no> wrote:
>
> > [snip]
>
> >>It is /always/ a superkey. It might be "candidate" (i.e. irreducible) as
> >>well; if not, it is a /proper superkey/. (Also, a tuple is not a key,
> >>but I'll quibble about that some other time:)
>
> > Why can't a tuple be a key? It does uniquely specify a tuple.
>
> Because a tuple is a value and a key is a constraint.
How do you isolate a single tuple ?

> > Sincerely,
>
> > Gene Wirchenko
>
> > Computerese Irregular Verb Conjugation:
> > I have preferences.
> > You have biases.
> > He/She has prejudices.
Received on Tue May 29 2007 - 10:54:59 CEST