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Don't knock those XML DTDs. You can only create small relatively simple things
with them - saves people from injurying themselves and others.
Same reason why you cannot buy automatic assault weapons (but I have mine
back-ordered from Walmart for when the NRA manage to get that repealed!)
It really must be Friday...
Quoting "Bullard, Claude L (Len)" <firstname.lastname@example.org>:
> You have a declarative system that can dynamically
> determine concepts from contexts? Or you have a
> pattern matcher? Or you have a human making maps?
> A registry is just another way to store apriori
> agreements plus a map.
> Ummm... I have an RFP in front of me that requires we
> deliver a DTD. Some subsumption is not yet complete.
> From: email@example.com [mailto:firstname.lastname@example.org]
> Unfortunately schema was never intended to perform that role!
> Not the least because it has no context driven mechanisms.
> Apart from that - way too many people think it can do this 'magic' because
> has been over sold - well beyond the original requirements the W3C started
> We started off with a DTD - simple mission to describe the structure
> permutations of an XML instance. XSD then subsumed that role. Snag is
> is able to deliver fully. It's all to easy to create an XML instance, or
> of instances, that look perfectly reasonable and straightforward that is
> hard to then describe in schema.
> I'm reminded of the situation in England in the 1500's - when Latin was
> the official legal language of law - but everyone uses English as the
> language. The solution beckons ; -)
> Quoting "Cox, Bruce" <Bruce.Cox@USPTO.GOV>:
> > In my world, attorneys speak "business rules" and IT folk speak "data
> > constraints". Often, their intention and extension are identical. A
> > really good schema is the membrane where these two sets touch each
> > other, that is, it is equally successful from both points of view.
> > Bruce B. Cox
> > SA4XMLT
> > +1-703-306-2606
> > -----Original Message-----
> > From: Thomas B. Passin [mailto:email@example.com]
> > Sent: Thursday, August 19, 2004 4:59 PM
> > To: firstname.lastname@example.org
> > Subject: Re: [xml-dev] Are people really using Identity constraints
> > specified in XML schema?
> > Roger L. Costello wrote:
> > > - The value of the <minimum-age> must be an integer. This is a
> > > constraint on the data. It will not change over time.
> > Ha! What happens when the government decides that some relevant age is
> > 67.5 years instead of 67?
> > > Therefore, an XML Schema should simply constrain <minimum-age> to be
> > > an integer. Higher level applications should implement the business
> > > rule that <minimum-age> be further constrained to 16.
> > >
> > > How would you characterize the distinction between "business rules"
> > > and "constraints on data"?
> > A tricky, tricky issue - what is or is not a "business rule". I suspect
> > that in practice most constraints that are not business rules are in
> > place for supposed programming reasons, or by force of habit.
> > In one project I work on, we have a data type that is a union of 1) an
> > enumeration of strings, 2) a string that follows a certain regex
> > pattern, and 3) an integer constrained to a certain range. No, don't
> > bother to ask - it's one of those multi-agency reconciliations.
> > --
> > Thomas B. Passin
> > Explorer's Guide to the Semantic Web (Manning Books)
> > http://www.manning.com/catalog/view.php?book=passin
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