Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]
From: Alexandr Savinov <savinov_at_host.com>
Date: Wed, 08 Jun 2005 15:11:26 +0200
Message-ID: <42a6ee91$1_at_news.fhg.de>
Date: Wed, 08 Jun 2005 15:11:26 +0200
Message-ID: <42a6ee91$1_at_news.fhg.de>
Ged Byrne schrieb:
> Alex,
>
> This all makes sense, but this is not how NULLs work in SQL databases.
>
> NULL behaves the way that you describe UNKNOWN.
>
> The scheme you describe could be implemented using the special values
> approah.
That is bad! From other posts I also made a conclusion that there is almost complete chaos in this area because different SQLs and DBMSs implement it differently and even in theory there is no unity how to treat it.
-- alex http://conceptoriented.comReceived on Wed Jun 08 2005 - 15:11:26 CEST