Path: newssvr20.news.prodigy.com!newsmst01.news.prodigy.com!prodigy.com!newsfeed.cwix.com!feed2.news.rcn.net!rcn!feed3.news.rcn.net!not-for-mail From: Jerry Gitomer Subject: Re: Any new thoughts on OTLT (One True Lookup Table) Date: Sat, 27 Mar 2004 23:30:54 -0500 User-Agent: Pan/0.14.2.91 (As She Crawled Across the Table) Message-Id: Newsgroups: comp.databases.theory References: <40483031.1F7E8889@hp.com> <404C7E5C.635C1EBC@hp.com> <5cCdnRxJhvQx4PjdRVn-jg@comcast.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Lines: 29 X-Trace: DXC=6^k4L0Rf>C>cGKCSLObU\20R]m=BkYWI7:6bU3OT9S9:gRjm4@;=_Y5d;;ZAijS4@6CCmLIW_Mb`6 X-Complaints-To: abuse@rcn.com Xref: newssvr20.news.prodigy.com comp.databases.theory:24834 On Sat, 27 Mar 2004 08:12:44 -0500, Laconic2 wrote: >> Doesn't OTLT have to include a third column, 'class' perhaps, with >> values 'state' and 'airline' respectively? >> > > Yes, it does. And that's precisely the problem with putting the code "PA" > in the same column twice, with two different meanings. Making use of the > "class" column, > requires a programmatic solution. > > We've taken a step away from self describing data. > > How does the new user of the data, whether person or automaton, "know" > that you have to qualify the "code" column with the "class" column? Is that > inherent in the two columns? Is it written in the metadata? No! > > > Is it inherent in the underlying subject matter? No! > > The new user "just has to know" that that was the intent of the designer, > and program accordingly. And that's what's wrong. In the real world we have documentation that developers are expected to refer to before they start coding. The reason has to do with the fact that the system will probably still be in use long after the original developers have moved on.