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Re: So what's null then if it's not nothing?

From: <>
Date: 23 Nov 2005 19:27:50 -0800
Message-ID: <>

JOG wrote:

> wrote:
> > JOG wrote:
> >
> > > Look, when you create a relation, you are defining a predicate. You are
> > > saying propositions that fit with these variables will be stored here.
> > > If you have proposition that does not fit due to absent information,
> > > and you try to insert it, you are trying to put a square peg in a round
> > > hole. That proposition DOES NOT MATHEMATICALLY BELONG THERE. It doesn't
> > > fulfill the predicate. Full stop.
> > >
> > > Hence any workaround which allows you to do this, whether practical,
> > > pragmatic or useful, is a hack. Calling nulls "special values" will not
> > > disguise this. I cannot see any room for maneuvre here. This of
> > > course, does not mean I will not use this hack on an all too regular
> > > basis, but I am absolutely aware of its incorrectness.
> >
> > I sense you're getting a bit excited about this.
> >
> > Look...
> >
> > If you have a text/string field and it can have an empty string what
> > have you got? What is the value of the data? How does that value differ
> > from "no value at all"? Question mark.
> Hi michael, I tried to answer this before - your logic there would say
> an empty set is equal to there being no set at all, which is incorrect.

No. It wouldn't. [sighs]

> This distinction was one of the breakthroughs in mathematics in the
> last century and I don't think we should start ignoring it now. J.

I didn't realise this. Can you supply any links to background on this breakthrough? It might provide some valuable reading to those who mistakenly equate NULL to "no set at all", or the absence of a set, when it should really be equated to the presence of an empty set.

Mike. Received on Wed Nov 23 2005 - 21:27:50 CST

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