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Home -> Community -> Usenet -> comp.databases.theory -> Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

From: Marshall Spight <marshall.spight_at_gmail.com>
Date: 9 Jul 2005 09:07:09 -0700
Message-ID: <1120925229.038425.257760@z14g2000cwz.googlegroups.com> 





I don't really see the value of the whole possrep thing. The
most basic example from TTM wouldn't work very well, because
point(x,y) and point(theta, r) *don't* have the same sets of
values except in some uncomputable platonic ideal universe.
You cannot give a precise conversion of point(1,1) to
point(theta, r). In addition, you have to write your conversions
routines by hand anyway, so you don't save anything there.



I just don't see what it buys you.



Tagged unions, a la ML, strike me as quite useful, however.




Marshall
Received on Sat Jul 09 2005 - 11:07:09 CDT












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