- From: jeroen bekaert <jbekaert@lanl.gov>
- Date: Tue, 15 Mar 2005 23:46:07 -0700 (MST)
- To: xmlschema-dev@w3.org
Hi all, I am wondering whether the derivation by extension constructs of the XML schemas below are correct: SCHEMA 1 defines a DIDBaseType, and several Complex Types (e.g. didmodel:StatementType) derived by extension from the DIDBaseType. SCHEMA 2 defines several Complex Types (e.g. didl:StatementType) derived by extension from the like-named (didmodel) Complex Types in Schema 1. Derivation by extension can be used to append new content after the content of the base type; however - if not mistaken - the structure of the base type must be kept unchanged. As such, it is not possible to derive a mixed content model from an element-only content model (and vice versa). The content type of the base type definition of SCHEMA 1 below is empty. Is it correct to derive (by extension) a content type 'mixed' of a base type definition with an empty content type? Can someone point me to the clause of the W3C XML Schema spec confirming/forbidding the below extension constructs? Many thanks Best regards Jeroen Bekaert SCHEMA 1: .... <complexType name="DIDBaseType" abstract="true"/> .... <element name="Statement" type="didmodel:StatementType" abstract="true"/> <complexType name="StatementType"> <complexContent> <extension base="didmodel:DIDBaseType"/> </complexContent> </complexType> .... SCHEMA 2 (imports SCHEMA 1): .... <element name="Statement" type="didl:StatementType" substitutionGroup="didmodel:Statement"/> <complexType name="StatementType" mixed="true"> <complexContent mixed="true"> <extension base="didmodel:StatementType"> <sequence> <any namespace="##any" processContents="lax" minOccurs="0"/> </sequence> <attribute name="mimeType" type="string" use="required"/> <attribute name="ref" type="anyURI"/> </extension> </complexContent> </complexType> .... -- Digital Library Research and Prototyping team Los Alamos National Laboratory PO Box 1663, MS P362 Los Alamos, NM, 87545, USA tel. +1 (505) 664 0580
Received on Wednesday, 16 March 2005 06:46:35 UTC