Re: Two-valued logic

From: --CELKO-- <joe.celko_at_northface.edu>
Date: 3 Jan 2004 08:43:29 -0800
Message-ID: <a264e7ea.0401030843.6b17ecd2@posting.google.com>

>> However, I don't know if that is really the case or if I just
happen to be reading the pro-two-valued logic folks. <<

Yep, you are. The entire SQL world is on 3VL and if Cood had his way, it would be a 4VL (TRUE, FALSE, "attribute exists for the entity, but value not known" and "attribute does not exists for the entity, so value cannot exist")

In fact, there is a whole area of "missing data" theory in the literature. Statistics have all kinds of "missing data" values, for example. Received on Sat Jan 03 2004 - 10:43:29 CST