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Re: RELAX NG and W3C XML Schema


At 10:24 AM 6/7/2002 -0700, Eric Sedlar wrote:
You are not supporting most of your assertions--why is mixed not "useful"?

Because it provides no constraints whatsoever on where textual content may appear, and because it's an odd extra pinned on to complex types without much thought for its implications.

RELAX NG does a far better job of supporting precise descriptions of mixed content in ways are considerably more predictable and easier to capture.

Why, if implementation is so difficult, are there so many available?

Because the people who created this horrible mess have the resources to implement it.

One of our goals with XML Schema is to use it as a replacement for SQL DDL
when creating tables in databases, and compiling it for faster validation.
One of the reasons that XML Schema is more constrained is that it allows for
more efficient implementation of this type of technology.  If you can't
describe the document structure in XML Schema, it will probably not form a
data structure that can be efficiently searched and updated using a database
(whether it is object-oriented or relational at its foundational layers).

If that's what you were really after, why exactly did you call it "XML Schema" and thereby inflict the needs for this practice on the rest of us XML users?

Gack. If I wanted SQL, I'd use SQL.

I agree that there is no need to privilege a particular XML structure
definition spec at this time.

Good. That will let this discussion proceed without further conflict.

These same battles will be fought out in the
individual IETF working groups anyway regardless of what this document says
anyways.  I just felt that there were a number of accusations about XML
Schema on this that were poorly supported that needed to be answered.

I think James Clark has already done an excellent job of deconstructing W3C XML Schema. If you would like me to repeat the performance, I probably can, though I don't have the time or his level of experience. Your grouping of his complaints effectively watered them down, so I guess I still consider most of them unanswered.

Simon St.Laurent
"Every day in every way I'm getting better and better." - Emile Coue