Re: 3 value logic. Why is SQL so special?
Date: 20 Sep 2006 02:57:29 -0700
Message-ID: <1158746249.821721.33570_at_b28g2000cwb.googlegroups.com>
Bob Badour wrote:
> JOG wrote:
>
> > Bob Badour wrote:
> >
> >>What is NULL if not the basis for 3 valued logic or 4 valued logic?
My answer to that question is embedded below. I do not see why threeor four-valued logic should be forbidden. Even less can i see how you can enforce users (database-designers) to create a four-valued type system if they should so desire. (Assuming the database has a sufficiently powerful typesystem: C++ comes in mind).
> >
> > An ugly hack to workaround the fact that most designers are either too
> > lazy or too lacking in pride to design their databases correctly?
>
> Um, well okay, but I guess I was asking for an answer from the folks who
> want to rationalize the ugly hack somehow.
Well Bob.... being on usenet is not a full time pastime for me and
currently I only have internet access from my job. My postings are thus
bound to be somewhat sparse. But I do not see what NULLS have to do
with database design. I could perfectly well live with a situation
where nulls were for some reason disallowed in "physical" tables. (But
do not see why they must be). The major problem of missing nulls is one
of supporting the end users who query my base tables; here a left join
is often quite nice to have.
/Peter Received on Wed Sep 20 2006 - 11:57:29 CEST