Re: XQuery (and XML) vs LISP

Mark Johnson wrote:
> Christopher Browne <cbbrowne_at_acm.org> wrote:
>
> The thing that has bothered me is that those promoting the relational
> model typically provide worthless examples, typically employee and
> department, and seem to almost religiously avoid non-trivial working
> examples, particularly those that might seem problematic for the
> scheme.

Employees and departments are tables that will exist in a (probably relational) database in the HR department of every corporation in the world. It is about as real-world an example as you can get. It may be the case that you don't write applications that do that sort of thing, but lots of people do.

When you're trying to communicate, producing examples that are illustrative while also as simple as possible is the best thing you can do. Many relational writers are very good at this.

If one belongs to the crowd that says, "I want a J2EE book, and the more it weighs the better it must be," one probably does not appreciate this perspective.

 > For example, what is a type? What goes in the 'set', as you express
> it, never mind any particular domain? Why is a book a 'type', when
> there are various sorts of books? Why is a chapter a 'type', when the
> chapters in the same book might be of a very different sort? Is the
> appendix which is more an index a type to itself? And so on. Are the
> paragraphs a 'type', and is the paragraph in chapter 4 different than
> the paragraph entities in relation chapter 5?

I don't understand your point here. It seems to be written to critique a set of types to describe a book. What types and what book? Or are you saying that type theory has nothing useful to say about books?

> To normalize things does
> it require literally hundreds and hundreds of 'relations'/tables to
> represent the structure?

How many classes does a Java program have? How many people does a company need?

> Just think of the 'joins'.

Joins are wonderful; I love thinking about them. I wish the programming languages I use had anything as powerful.

> And wasn't the RM
> intended to free people from the 'tyranny of structure'?

No.

And anyway, you can't not have structure.

Marshall Received on Fri Feb 17 2006 - 16:59:51 CET