File: Schema.xsd <?xml version="1.0" encoding="UTF-8"?> <xs:schema targetNamespace="http://www.oreilly.com/xslt" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="http://www.oreilly.com/xslt"> <xs:element name="part"> <xs:complexType> <xs:sequence> <xs:element ref="name" minOccurs="1" maxOccurs="1"/> </xs:sequence> <xs:attribute name="part-id" type="xs:ID" use="required"/> </xs:complexType> </xs:element> <xs:element name="name" type="xs:string"/> <xs:element name="partref"> <xs:complexType> <xs:attribute name="refid" type="xs:IDREF" use="required"/> </xs:complexType> </xs:element> </xs:schema>