Re: No exceptions?

"Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message news:MTzpg.4709$pu3.109666_at_ursa-nb00s0.nbnet.nb.ca...
> Jon Heggland wrote:
>
> > Bob Badour wrote:
> >
> >>Jon Heggland wrote:
> >>
> >>>"Every attribute" would also be a superkey (speaking loosely). The
empty
> >>>set is a subset of every set.
> >>
> >>I respectfully suggest the confusion caused by your use of key without
> >>the 'candidate' qualification demonstrates exactly why we have the term.
> >>I suppose irreducible key would do just as well, but for historical
> >>reasons, candidate key already means an irreducible key.
> >
> > I don't think the confusion is on my part. "Key" (as opposed to
> > "superkey") already implies irreducibility; that's the point of the
> > superkey/key distinction. A "candidate key" is certainly irreducible
> > (due to being a key), but "irreducible key" is redundant.
>
> Candidate key, superkey and proper superkey all have different precise
> meanings and all of them are keys.
>
> A definition is like a contract for communication and understanding.

Well done. However, I would slighlty edit: A definition IS A contract for communication.

> When you arbitrarily redefine key to mean candidate key, you breech that
> contract and the result of that breech is confusion.

Do you really mean "breech" or did you mean "breach" ?

 Whether the
> confusion is on your part, you are nevertheless the cause of the
confusion.
>
> By redefining key to mean candidate key, one loses the term that means
> key. By redefining superkey to mean proper superkey, one loses the term
> that means superkey.
>
> Your laziness about typing the full names causes confusion and
> interferes with communication.
Received on Sat Jul 01 2006 - 23:38:04 CEST