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Forgot the link: [1] http://www.topologi.com/public/Schtrn_XSD/Paper.html > -----Original Message----- > From: Jeff Lowery [mailto:jlowery@s...] > Sent: Tuesday, March 26, 2002 11:50 AM > To: 'John Cowan'; matthew.gertner@s... > Cc: xml-dev@l... > Subject: RE: RELAX NG Marketing > > > If the proposed solution doesn't address the requirements, > then there is no > choice but to seek a different solution. It's that simple. > > True, the "different" solution may involve hacking the > original. This is > the approach one standards body I know of seems to be taking. > Their data > model requires unordered element content (everywhere). They > have an XML > Schema for this data model, but the XML Schema language > severely restricts > the ability to specify unordered content. Their workaround > has been to use > unbounded model groups. > > That works, so long as you don't care about validating the > cardinality of > children. Since it's kinda important in most cases, though, > the current > proposed workaround to the workaround is to add appinfo > annotations to each > child element that specifies its true cardinality. A Xerces > plugin is then > used to check the cardinality of children based on the > appinfo annotations. > > Needless to say, this is a truly ugly hack. And tool dependent. > > As an aside, similar solutions have been proposed elsewhere > using Schematron > rules in appinfo annotations. These may be ugly, too, but > have at lease some > appeal if only because you get added Schematron constraint > checking in the > bargain. [1] > > Inelegant as appinfo cardinality annotations may be, I have > suggested three > alternatives, none of which are being accepted with open arms: > > 1) add a constraint to the data model that requires children > to be ordered. > (I have sympathy for those who wish not to enforce artificial > constraints on > their data model.) > 2) Use RELAX-NG + XSD datatypes. (Politically incorrect.) > 3) Fix the cardinality definitions in the XSD schema and use an XSLT > transform to order children prior to validation. (Seems simplest, but > what's the performance hit for a large document? Maybe Tom > Passin can answer > that one.). > > There's probably a couple of other options I'm not thinking > of. Feel free > to share. > > -- Jeff > > > > ----------------------------------------------------------------- > The xml-dev list is sponsored by XML.org <http://www.xml.org>, an > initiative of OASIS <http://www.oasis-open.org> > > The list archives are at http://lists.xml.org/archives/xml-dev/ > > To subscribe or unsubscribe from this list use the subscription > manager: <http://lists.xml.org/ob/adm.pl> >
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