Path: text.usenetserver.com!out02b.usenetserver.com!news.usenetserver.com!in02.usenetserver.com!news.usenetserver.com!pd7cy1no!pd7cy2no!shaw.ca!pd7urf2no.POSTED!53ab2750!not-for-mail X-Trace-PostClient-IP: 24.84.208.66 From: paul c User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 Newsgroups: comp.databases.theory Subject: Re: NULLs: theoretical problems? References: <46b9b627$0$4048$9a566e8b@news.aliant.net> <1186582837.431878.213670@22g2000hsm.googlegroups.com> <46b9dc62$0$4020$9a566e8b@news.aliant.net> <1186598966.500240.251730@19g2000hsx.googlegroups.com> <46ba14f1$0$4063$9a566e8b@news.aliant.net> <1186603776.661467.76070@19g2000hsx.googlegroups.com> <46ba2544$0$4028$9a566e8b@news.aliant.net> <1186607092.314530.168770@x40g2000prg.googlegroups.com> In-Reply-To: <1186607092.314530.168770@x40g2000prg.googlegroups.com> X-No-Archive: yes Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Lines: 21 Message-ID: Date: Wed, 08 Aug 2007 21:21:17 GMT NNTP-Posting-Host: 64.59.144.74 X-Complaints-To: abuse@shaw.ca X-Trace: pd7urf2no 1186608077 64.59.144.74 (Wed, 08 Aug 2007 15:21:17 MDT) NNTP-Posting-Date: Wed, 08 Aug 2007 15:21:17 MDT Organization: Shaw Residential Internet Xref: usenetserver.com comp.databases.theory:166158 X-Received-Date: Wed, 08 Aug 2007 17:21:18 EDT (text.usenetserver.com) Marshall wrote: > ... > Concepts such as natural numbers or relations or functions > do not exist in the same way that rocks and birds exist. > NULL "exists" in exactly the same way that 5 exists; ... Heh, and in the same way that 5 doesn't exist? ... the > only distinctions to be made between abstractions is in > their behavior and our judgment of their usefulness. I say > this even though I have a very low opinion of NULL. > ... Even if not only in the mind's eye, existence isn't enough to make a formal system out of. At least the SQL people can claim they have a definition of sorts, even though it is an absurd one. Maybe they don't care, maybe they were just obeying orders. p