Re: Date of Birth as an attribute

That's a good point about calling it the "requirements or analysis model".

It reminds me of something. Back when I was first looking into the Object Oriented way of thinking, I read "Object Oriented Analysis" by Coad and Yourden. Believe it or not, I actually liked OOA better than ER, even though I'm more familiar and more comfortable with ER.

But one thing I would say. Back when OOA was written, "Object Oriented" seemed to place a heavy premium on analysis, putting a lot of resources, and more importantly a lot of time, into an in depth understanding of the problem domain. I find that difficult to reconcile with the attitude expressed by OO enthusiasts in this forum that there's no time to learn the subject matter in any depth before starting the design and coding.

Maybe the argument isn't about models at all. Maybe it's about how much time you devote to analysis versus design and development.

About the difference between logical and physical models. For one thing, schema objects, like tables belong in both models, but database objects like tablespaces belong only in the physical model. Arbitrary limitations, made for capacity or speed, belong in the physical model as well. This is all my opinion, of course.

One time, a colleague and I did our logical design for a certain DBMS, and at the last minute, the DBMS was changed on us. We had to do the physical design from scratch. But we were pleased that we had built no DBMS product dependencies into our logical model.

That was no accident. It made it a lot easier to react on the fly.

BTW, What's the difference between ER modeling and ERD Modeling? Received on Wed Apr 07 2004 - 23:48:12 CEST