Re: Does Codd's view of a relational database differ from that ofDate& Darwin? [M.Gittens]
From: Gene Wirchenko <genew_at_ucantrade.com.NOTHERE>
Date: Wed, 08 Jun 2005 10:04:27 -0700
Message-ID: <u58ea1lun0h1k3usj86h9tot2hv6s53sat_at_4ax.com>
Date: Wed, 08 Jun 2005 10:04:27 -0700
Message-ID: <u58ea1lun0h1k3usj86h9tot2hv6s53sat_at_4ax.com>
On Tue, 07 Jun 2005 17:42:23 +0200, Alexandr Savinov
<savinov_at_host.com> wrote:
[snip]
>To say "if NULL means unknown" is the same as to say "if 0 is equal 1"
>or "if empty set is full set". Unknown and null are two different things
>and deserve to have to special designations.
>
>NULL means absence
>UNKNOWN means presence with unknown identity
What term would you use for the case of it being unknown whether the value exists?
[snip]
Sincerely,
Gene Wirchenko Received on Wed Jun 08 2005 - 19:04:27 CEST