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> -----Original Message----- > From: Amelia A Lewis [mailto:amyzing@t...] > Sent: Monday, June 10, 2002 7:35 PM > To: Aaron Skonnard > Cc: 'Tim Bray'; xml-dev@l... > Subject: RE: W3C Schema: Resistance is Futile, says Don Box > > The introduction of > data types for "simple" (text nodes and > attributes) nodes provides a way to validate the text, beyond > existing parsed character data (the only valid type for text > nodes in DTD), CDATA, Name, Token, NCName, QName, ID, IDREF, > and the derived list types. Note that the attribute types > are almost exclusively concerned with reference types (XML > versions of pointers), and that at least two of them actually > embed co-occurrence constraints (ID and IDRef), which cannot > be modeled in any of the current schema languages, except by > deus ex specificatia. A.) I wouldn't call ID and IDREF co-occurrence constraints but instead identity constraints of which W3C XML Schema has xs:key, xs:keyref and xs:unique B.) Schematron and to a lesser extent RELAX NG support co-occurrence constraints. -- PITHY WORDS OF WISDOM The shortest distance between two points is under repair. This posting is provided "AS IS" with no warranties, and confers no rights.
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