Re: So what's null then if it's not nothing?
Date: 23 Nov 2005 18:40:49 -0800
Message-ID: <1132800049.377193.266290_at_f14g2000cwb.googlegroups.com>
michael_at_preece.net wrote:
> JOG wrote:
Hi michael, I tried to answer this before - your logic there would say
>
> > 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.