Re: No exceptions?
Date: Sat, 01 Jul 2006 21:38:04 GMT
"Bob Badour" <bbadour_at_pei.sympatico.ca> wrote in message
> Jon Heggland wrote:
> > Bob Badour wrote:
> >>Jon Heggland wrote:
> >>>"Every attribute" would also be a superkey (speaking loosely). The
> >>>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
> contract and the result of that breech is confusion.
> confusion is on your part, you are nevertheless the cause of the
> 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