Re: Temporal database - no end date

>> Temporal Data & the Relational Model,by C.J. Date, Hugh Darwen, Nikos Lorentzos (Morgan Kaufmann, 2002); ISBN 1-55860-855-9 .. I will take a look. <<

You had better look fast. This book was a failure on several levels. Date uses the Chronon model of time, which was discredited by Zeno's paradoxes. The vast majority of temporal database researchers use the half-open interval model for time. That is being kind -- Lorentzos is the only person I have seen who uses Chronons.

A chronon is a quantum of time that originally had a fad in physics and the term spread -- remember the tachyon fad (a hypothetical particle that always travels faster than the speed of light) that disappeared with a one page logical proof of impossibility? Physics is bad about that kind of thing.

Date's book invents its own language rather than giving SQL, so programmers cannot use it in their apps. You also wind up with the weird thing that sequentially numbered salesman can be handled with the same operators as durations.

So, the book was rejected by both the working and academic communities. Sales were awful in spite of Date's & Darwen's name on it. What really did it in was an unfortunate attack on Snodgrass by Date that got to be minor scandal in the RDBMS community and an embarrassment to Morgan-Kaufmann. Received on Tue Jan 16 2007 - 10:25:19 CST