A question for Mr. Celko
Date: 16 Jul 2004 20:35:33 -0700
Message-ID: <72f08f6c.0407161935.70b95a1d_at_posting.google.com>
I was browsing through the archives and found this gem, which remains unanswered. I for one would very much like to know what you are referring to, and why the solutions proposed in the book are "weird"
> 4) He supports Chris Date's temporal model, which advocates a chronon
> model for temporal data and some weird extensions to the relational
> model for them. Even before Rick Snodgrass did his work in the field,
> Zeno's paradoxes and Einstein's physics showed that time is a
> continuum and not a set of discrete points, so time is made up of
> durations that cannot be defined as countable sets of points.
The domain of integers is infinite, but we are quite content to model it with a finite set. In what way is this different?
There are *no* extensions to the relational model proposed in the book Temporal Data and the Relation Model. This is quite different from Rick Snodgrass's approach, which requires such Information Principle violating notions as hidden columns. All the operators introduced in the temporal book are shorthands for more detailed *relational* expressions.
From Temporal Data and the Relational Model, p. 56 "In other words, the approach to temporal databases that we advocate invovles no changes to the classical relational model!"
So what extensions precisely are you claiming are introduced by Date, Darwen and Lorentzos' work in this area?
Bryn Received on Sat Jul 17 2004 - 05:35:33 CEST