2084 2005-09-09 03:22:09 +0000 R-094: Issues with identity constraints and derivation by restriction 2012-12-04 00:52:40 +0000 1 1 1 Unclassified XML Schema Structures: XSD Part 1 1.0 only All Windows 3.1 NEW needsDrafting P2 normal --- 1 sandygao David_E3 www-xml-schema-comments oldest_to_newest 5977 0 sandygao 2005-09-09 03:22:09 +0000 In the section titled 'Schema Component Constraint: Particle Restriction OK (Elt:Elt -- NameAndTypeOK)', the following is mentioned: "For an element declaration particle to be a valid restriction of another element declaration particle all of the following must be true: 5 R's declaration's {identity-constraint definitions} is a subset of B's declaration's {identity-constraint definitions}, if any." The issues are: the spec should be clarified to state what "subset" means the subset requirement runs the wrong way -- the derived element's IC's should be a _super_set of the base's. an element decl in a restriction can't have the same ICs as its corresponding decl in the base, because that would violate the named-components-are-unique constraint The original questions were posted to the schema-dev list. Henry summarized the issues in the following mail on schema-comments: http://lists.w3.org/Archives/Public/www-xml-schema-comments/2001OctDec/0187.html and: http://lists.w3.org/Archives/Public/www-xml-schema-comments/2001OctDec/0188.html 5978 1 sandygao 2005-09-09 03:22:53 +0000 See: http://lists.w3.org/Archives/Member/w3c-xml-schema-ig/2002Jan/0072.html Resolution: Henry Thompson will create an erratum that highlights the current limitations (see bullet 3 above). The WG may revisit this issue in a future specification.