RE: building an object model of a XML schema

[Michael Brennan <Michael_Brennan@allegis.com>]

> From: Jeff Lowery [mailto:jlowery@scenicsoft.com]

<snip/>

> Right now, that information is missing from XML Schema, and 
> various code
> generation implementations have their own unique ways of adding the
> information. As it should be? I hope not.

Actually, I would not want to see that in XML Schema. If XML Schema were
intended as a data modelling language, rather than as a "foundation" spec
for other XML specs, I wouldn't have a problem with this. But in my mind,
XML Schema has already veered too far in this direction, and this has
nothing to do with XML; it has more to do with how particular applications
*use" XML, and there are plenty of applications that deal with XML that have
no use for this stuff.

I see great utility in XML Schema, but there is also in my mind a sharp
distinction between modelling the XML syntax for a document type, and
modelling the information my application will synthesize and use from that
XML document. Some might find it useful to combine the two, but the whole
XML world should not have to follow their lead. I much prefer to keep the
two separate.

Note, that it is also possible to annotate an XML Schema with attributes and
elements from other namespaces. You can add application specific info to the
model to suit your needs in a way that is compatible with other schema
processors (they can ignore your application specific info). You can also do
this with RELAX NG. This is a sound approach, IMHO, to let users extend the
model in useful ways without the core XML Schema grammar having to
accomodate everyone's use case.