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Hello,
I am currently developing an XML Schema for a university course catalogue. To ease maintenance, i thought of defining "module"s that inherit some or all child-elements from another "module" (i call those "derivedModule"). Any element that is not present inside of a "derivedModule" should be copied from its "baseModule" (of type "module", the one referred to by an XS:IDREF, not a new type of element). Right now, I use XS:ID and XS:IDREF to refer to a "module", and a XSL-Template eventually combines the "derivedModule" with it's "baseModule". It checks every child-element inside of a referred "baseModule" for an occurence of the same element in "derivedModule" and then copies either first or latter (if found). I am not happy with this solution, as it feels wrong to have part of the structural definition, the relation between a "derivedModule" and a "module" (or it's children) as part of the stylesheet. Now I am wondering whether it is actually possible to define such relations within an XML Schema, or whether it is against the philosophy behind XML. I am thankful for any suggestions, Andreas ---- Definiton for a "Module": <xs:complexType name="ModulType"> <!-- Modul --> <xs:sequence> <xs:element maxOccurs="1" minOccurs="1" name="Name" type="xs:string"/> <!-- Full name --> <xs:element maxOccurs="1" minOccurs="1" name="Modulgruppe" type="xs:string"/> <!-- Group for combination --> .... <xs:element maxOccurs="1" minOccurs="1" name="Bemerkung" type="FormatierterTextType"/> <!-- Annotation --> </xs:sequence> <xs:attribute name="id" type="xs:ID" use="required"/> <!-- ID --> </xs:complexType> Definition for a "derivedModule": <xs:complexType name="AbgeleitetesModulType"> <!-- referring Module--> <xs:sequence> <xs:element name="Basismodul" maxOccurs="1" minOccurs="1"> <!-- ID of baseModule to refer to--> <xs:complexType> <xs:simpleContent> <xs:extension base="xs:IDREF"> <xs:attribute name="wahl" type="xs:string"/> </xs:extension> </xs:simpleContent> </xs:complexType> </xs:element> <xs:element maxOccurs="1" minOccurs="0" name="Name" type="xs:string"/> <!--optional elements which overwrite those of the baseModule-> <xs:element maxOccurs="1" minOccurs="0" name="Modulgruppe" type="xs:string"/> .... <xs:element maxOccurs="1" minOccurs="0" name="Bemerkung" type="FormatierterTextType"/> </xs:sequence> <xs:attribute name="id" type="xs:ID" use="required"/> <!-- new ID --> XSL-Template to combine those two for further processing: <xsl:template match="m:abgeleitetesModul"> <xsl:attribute name="id"><xsl:value-of select="./@id" /></xsl:attribute> <xsl:variable name="basisID" select="m:Basismodul/text()" /> <xsl:variable name="abgModul" select="." /> <xsl:for-each select="//m:Modulhandbuch/m:Studiengang/m:Modul[@id=$basisID]/*"> <!-- Look for elements in baseModul, then check for occurences in derivedModule--> <xsl:variable name="name" select="./local-name()" /> <xsl:choose> <xsl:when test="$abgModul/*[name() = $name]"> <xsl:apply-templates select="$abgModul/*[local-name() = $name]" mode="Inhalte" /> <!-- copy element from derivedModule --> </xsl:when> <xsl:otherwise> <xsl:apply-templates select="." mode="Inhalte" /> <!-- else copy element from baseModule --> </xsl:otherwise> </xsl:choose> </xsl:for-each> </xsl:template>
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