Re: The BOOLEAN data type

From: Alfredo Novoa <alfredo_at_ncs.es>
Date: 11 Apr 2003 07:34:50 -0700
Message-ID: <e4330f45.0304110634.2ce8d49e@posting.google.com>

71062.1056_at_compuserve.com (--CELKO--) wrote in message news:<c0d87ec0.0303311011.2966d628_at_posting.google.com>...
> There were a few reason for not having it in SQL-92.
>
> To be a datatype in SQL, you have to be NULL-able. If you allow a
> LOGICAL datatype, then it has to be TRUE, FALSE, UNKNOWN and be
> NULL-able! But NULL does not work with AND, OR and NOT. Then there
> is the problem that an empty scalar subquery is cast as a NULL. The
> CHECK() constraint in the DDL accepts predicatres that test UNKNOWN,
> while ON and WHERE in the DML do not. It gets to be a mess really
> fast.

I am reading the SQL 2003 working drafts, and I am surprised to see that a boolean type was finally added.

Regards
Alfredo Received on Fri Apr 11 2003 - 09:34:50 CDT