Re: 3vl 2vl and NULL

From: x <x_at_not-exists.org>
Date: Tue, 6 Dec 2005 11:07:07 +0200
Message-ID: <dn3kc4$2cc$1@domitilla.aioe.org>

"x" <x_at_not-exists.org> wrote in message
news:dn3k8a$27e$1_at_domitilla.aioe.org...
>
> <michael_at_preece.net> wrote in message
> news:1133835469.329650.234930_at_g14g2000cwa.googlegroups.com...
> > What type of liquid is stored in an empty mug? Is it "unknown"? No - it
> > is not an unknown type of liquid. It is no liquid. The value of the
> > "liquid" column for the row would be empty. It would be NULL.
>
> You must not mix dirty empty mugs, clean empty mugs, full mugs, partial
> filled mugs and mugs with an unknown liquid.
> This would be a mess.

But isn't this why we have databases (and DBMSs) in the first place ? :-) Received on Tue Dec 06 2005 - 03:07:07 CST