Re: Date is Incomplete - database application software and database theory

> The same author reserves one diagram and perhaps a few sentences
> in regard to the applications layer in his "Intro to Database Systems".
> I will keep a look out for this other work, but his major work is
> flawed - for the reasons given.

This is not his major work. It is an introduction to database systems, not application development. Why should you be surprised that it doesn't cover application development? Is this the only thing you've read of his? You really need to get some more reading time in.

> > The relational model cannot possibly have anything to say
> > about the *implementation* of applications based on it.
>
> This statement is the common response by RM supporters.
> Date says the same thing. You're just quoting chapter and verse.

The relational model is *intentionally* silent about implementation. Are you arguing that we should dictate the method of implementation for DBMS vendors? What would be gained?

> The relational model of the data has alot to say about ongoing
> change management of database systems after implementation
> because the data schema in most organisations change in the
> course of time.
>
> Every change management exercise can be viewed as a mini-
> pre-implementation exercise and in this, even by your own
> definitions, the RM is a useful tool to map and consider these
> changes to the data existent (implemented) structure.

I'm sorry, I can't unravel these paragraphs.

> > We already have it. It's called the relational model.
>
> It is a model of data. What needs to be modelled is something
> slightly in excess of this "data alone", and includes processes
> and applications, with respect to the organization.

It is a model of data that includes provisions for operators to manipulate the data. It is *not* data alone. Data by itself wouldn't be very useful would it.

> > So I'll ask
> > you once again, have you read What Not How?
>
> Date cannot get things right in his major publication concerning
> an "introduction to database systems". What should I be looking
> for in these other works?

So if you wrote a textbook surveying database management systems and database theory, you would start with application development? I'm glad you're not writing the textbooks.

> If you cannot tell the difference between data and intelligence,
> or perceive that they need to modelled in a different manner,
> then how am I to assess your assessment?

It is you who is claiming that the relational model does not support "intelligence", not me. You're assertion that the model is "just data" is simply wrong. If you do not understand the fundamental definition of the relational model, how am I to assess your critique of it? This is why I asked you to define the relational model when we first started this little odyssey. I should have pushed you harder to provide one. Received on Mon May 24 2004 - 18:03:04 CEST