I have used Schematron for tailoring XML schemas for specific requirements.
I came across this defining specifications for using the Election Markup
Language for messages between electoral registers in the UK. There was no
need to access external documents, so I can't help there, but I had to
produce 15 Schematron schemas, each using a subset of a larger set of rules.
I think that this might be what you mean by "controlling the Schematron
elegantly across a set of schemas".

I did this by defining each of the rules in a spreadsheet (with columns for
rule, context, assert/report etc), then having a column for each of the 15
message types saying whether that rule applied. I then used a macro to
generate some simple XML from this and then a stylesheet to produce the 15
Schematron schemas under the control of a simple ASP script. I expect a real
programmer could find a better way. Apart from the ease of only modifying a
single spreadsheet for any changes, this had the advantage that the
spreadsheet was much easier for the software suppliers that would be using
the Schematron to understand.

I have submitted this as a case study for XTech 2006.

Regards

Paul Spencer

> -----Original Message-----
> From: bryan rasmussen [mailto:rasmussen.bryan@g...]
> Sent: 04 January 2006 13:08
> To: xml-dev@l...
> Subject: [xml-dev] schematron for xml schema validation
>
>
> Hey
> I'm doing a little schematron for validation of spec required xml
> schema structure, some of the validation rules cannot be done by
> schematron itself as it involves doing validation across external
> documents (I am focusing on a schematron that will work in all
> implementations so use of document function etc. not doable.)
>
> Anybody have experience with this problem, ideas for controlling the
> schematron elegantly across a set of schemas?
>
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