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RE: Separate data from rules ... is the XML Schema 1.1 <assert

• From: "Michael Kay" <mike@saxonica.com>
• To: "'Costello, Roger L.'" <costello@mitre.org>,<xml-dev@l...>
• Date: Wed, 17 Jun 2009 15:36:57 +0100

> 
> What is a "structural rule?"
> 
> In XML Schema 1.0 the answer was clear: anything that 
> required computation, if-then-else logic, inference, and 
> co-constraints could not be placed in XML Schema, and was 
> therefore placed in Schematron) All rules were expressed and 
> managed by Schematron.

No, I think that's post-hoc rationalisation. I don't think the split between
structural rules and business rules equates at all closely to the split
between grammar and predicates. You can say in XSD that a manager must have
at least five employees, which is definitely a business rule (and a bad
one); but it takes Schematron to say that a paragraph cannot appear nested
within another paragraph unless there is an intervening table, which is in
my book a structural rule - if indeed there is a black-and-white
distinction, which I doubt. The world is fuzzy.

Regards,

Michael Kay
http://www.saxonica.com/
http://twitter.com/michaelhkay 

• Follow-Ups:
  • RE: Separate data from rules ... is the XML Schema 1.1<assert> element a step backwards?
    • From: "Costello, Roger L." <costello@mitre.org>

• References:
  • Separate data from rules ... is the XML Schema 1.1 <assert> elementa step backwards?
    • From: "Costello, Roger L." <costello@mitre.org>
  • Re: Separate data from rules ... is the XML Schema 1.1<assert> element a step backwards?
    • From: Frank Manola <fmanola@acm.org>
  • RE: Separate data from rules ... is the XML Schema 1.1<assert> element a step backwards?
    • From: "Costello, Roger L." <costello@mitre.org>
  • RE: Separate data from rules ... is the XML Schema 1.1 <assert> element a step backwards?
    • From: "Michael Kay" <mike@saxonica.com>
  • RE: Separate data from rules ... is the XML Schema 1.1<assert> element a step backwards?
    • From: "Costello, Roger L." <costello@mitre.org>