[EMAIL PROTECTED] wrote:
What you seem to be saying here is "I can add a record type whenever I
need it and call it whatever I want".
So in a hospital, a doctor decides for some reason he needs to track toe
size of the patient over treatment. So he adds in a toe-size tag
<toe-size>3</toe-size>
And records that with every visit.
Doctors wouldn't do that. (Well noted XML guru Jonathan Borden, M.D.
might but most doctors wouldn't.) Instead they'd fill out a form just
like they do today.
The difference is that when the form doesn't let them include the
information they need, they can ask the devs to expand the form, and the
devs can do that without breaking all their existing databases. if the
devs are really good, they'll have figured out how to organize the forms
to allow doctors to expand it without realizing that's what they're doing.
Certainly SQL databases can be evolved, but it's really hard to do. Read
Refactoring Databases by Scott Ambler one of these days to see exactly
how hard it is; but it is possible. Scott proved that. However when
working on the book he was told repeatedly by data professionals that
what he was proposing was impossible. he wrote the book to prove that it
wasn't impossible, merely difficult.
In XML land, refactoring databases goes from merely possible to actively
encouraged and expected.
--
Elliotte Rusty Harold [EMAIL PROTECTED]
Java I/O 2nd Edition Just Published!
http://www.cafeaulait.org/books/javaio2/
http://www.amazon.com/exec/obidos/ISBN=0596527500/ref=nosim/cafeaulaitA/
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