Path: dp-news.maxwell.syr.edu!spool.maxwell.syr.edu!drn.maxwell.syr.edu!news.maxwell.syr.edu!border1.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!pd7cy2so!pd7cy1no!shaw.ca!pd7tw3no.POSTED!53ab2750!not-for-mail X-Trace-PostClient-IP: 24.81.152.157 From: paul c User-Agent: Mozilla Thunderbird 1.0.2 (Windows/20050317) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.databases.theory Subject: Re: Does Codd's view of a relational database differ from that ofDate& Darwin? [M.Gittens] References: <1117636456.185385.128930@g44g2000cwa.googlegroups.com> <3R6oe.1962$F7.1337@news-server.bigpond.net.au> <42a40b89$1@news.fhg.de> <42a4246c$0$41930$ed2619ec@ptn-nntp-reader03.plus.net> <42a42c05$1@news.fhg.de> <42a45433$0$41915$ed2619ec@ptn-nntp-reader03.plus.net> <5qm8a19q4nb9avbmhrik5nj5u35vujspsj@4ax.com> In-Reply-To: <5qm8a19q4nb9avbmhrik5nj5u35vujspsj@4ax.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Lines: 25 Message-ID: Date: Mon, 06 Jun 2005 15:02:17 GMT NNTP-Posting-Host: 64.59.144.74 X-Complaints-To: abuse@shaw.ca X-Trace: pd7tw3no 1118070137 64.59.144.74 (Mon, 06 Jun 2005 09:02:17 MDT) NNTP-Posting-Date: Mon, 06 Jun 2005 09:02:17 MDT Organization: Shaw Residential Internet Xref: dp-news.maxwell.syr.edu comp.databases.theory:31251 Alfredo Novoa wrote: > On Mon, 06 Jun 2005 14:48:35 +0100, Paul wrote: > > >>I guess the other claim against NULLs is that they make things more >>complex and less intuitive, which is a more subjective point. You could >>argue that Darwen's method of avoiding NULLs is more complex that using >>NULLs in the first place. > > > Nulls undermine the conceptual integrity of the Relational Model which > is based in predicate logic. > > A tuple with nulls does not match to a logical proposition. > > This causes many problems. Some of them were pointed by Eric. > > > Regards > i'm an admirer of Date's but i have to say i like your answer. no Latin to look up, either. p