Re: A question for Mr. Celko

>> Joe Celko said that? Interesting, because I usually get the same
reaction
when talking to colleagues of mine that actually do research in the field of temporal databases. <<

See? I'm smarter than I look!

>> One criticism I heard is that to simulate the PACK and UNPACK
operators you have to use operators that violate 1NF as it is usually understood. <<

I could almost live with the use of a "set of time points" in one column as a poor way to model a continuum; when Date Packed a "continuum of salesman numbers" into one of these things, I just could not take it.

If you go to the back of the book and look at the diagrams (which I wish had appeared sooner to make the model easier to see), he has many redundant ways to represent the same data. But wasn't one of Date's objections to SQL that we have many redundant ways to represent the same data in SQL?

The final thing was the claim that his extensions were still inside the Relational Model. He meant his version, not Codd's, not SQL's and I am not even sure about that.

And before I forget, Rick put his book up on his University website in PDF. Received on Sun Jul 18 2004 - 03:21:55 CEST