Re: Demo: Modelling Cost of Travel Paths Between Towns

"Alan" <alan_at_erols.com> wrote in message news:2vhas0F2lnpsgU1_at_uni-berlin.de...
> According to ISO, we can assign the value 0000 or 2400 to midnight. Let's
> look at another time, say 2 PM, or 1400 . Do we assign two values to 1400?

Believe it or not, this is a problem in "normalization". Not "data normalization" as we ordinarily speak of it in database discussions, but normalizations nonetheless.

Let's say that we are given two times, and asked whether they are equal or not.

Here are the two times:

2004.11.11 24:00
2005.11.12 00:00

The above form is for illustration purposes only.

Now a naive comparator would answer the question "no". But a comparator that really understands what we are talking about might take a closer look, and come up with the answer: "yes". I like the answer "yes", myself, better.

In fact, I would like the "time type engine" whenever it's done some calculation on time, (like adding an "interval" to a "base time") to perform one final step, before delivering the result to the outside world. If a computation happened to result in 2004.11.11 24:00, I would want it to convert it to 2005.11.12 00:00. And I would call this final step "normalizing the result".

Once the results of a computaion have been "normalized" , a naive comparator can test for equality by just comparing the representations. Right? Received on Fri Nov 12 2004 - 13:08:06 CET