XML Tutorial/XML Schema/Reference

Referencing Already Defined Elements

   <source lang="xml">

You can only reference element declarations within sequences, sets of choices, unordered groups, and named group definitions. Each reference may contain distinct values for minOccurs and maxOccurs.

File: Data.xml <?xml version="1.0"?> <library>

 <book id="b0836217462" available="true"> 
   <isbn>1111111111</isbn> 
   <title lang="en">Java</title> 
   <author id="CMS"> 
     <name>name</name> 
     <born>1998-11-26</born> 
     <dead>2000-02-12</dead> 
   </author> 
   <character id="PP"> 
     <name>Swing</name> 
     <born>1996-08-22</born> 
     <qualification>Yes</qualification> 
   </character> 
   <character id="Web"> 
     <name>JSP</name> 
     <born>1997-10-04</born> 
     <qualification>No</qualification> 
   </character> 
 </book> 

</library> File: Schema.xsd <?xml version="1.0"?> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">

 <xs:element name="name" type="xs:string"/> 
 <xs:element name="qualification" type="xs:string"/> 
 <xs:element name="born" type="xs:date"/> 
 <xs:element name="dead" type="xs:date"/> 
 <xs:element name="isbn" type="xs:string"/> 
 <xs:attribute name="id" type="xs:ID"/> 
 <xs:attribute name="available" type="xs:boolean"/> 
 <xs:attribute name="lang" type="xs:language"/> 
 <xs:element name="title"> 
   <xs:complexType> 
     <xs:simpleContent> 
       <xs:extension base="xs:string"> 
         <xs:attribute ref="lang"/> 
       </xs:extension> 
     </xs:simpleContent> 
   </xs:complexType> 
 </xs:element> 
 <xs:element name="library"> 
   <xs:complexType> 
     <xs:sequence> 
       <xs:element ref="book" maxOccurs="unbounded"/> 
     </xs:sequence> 
   </xs:complexType> 
 </xs:element> 
 <xs:element name="author"> 
   <xs:complexType> 
     <xs:sequence> 
       <xs:element ref="name"/> 
       <xs:element ref="born"/> 
       <xs:element ref="dead" minOccurs="0"/> 
     </xs:sequence> 
     <xs:attribute ref="id"/> 
   </xs:complexType> 
 </xs:element> 
 <xs:element name="book"> 
   <xs:complexType> 
     <xs:sequence> 
       <xs:element ref="isbn"/> 
       <xs:element ref="title"/> 
       <xs:element ref="author" minOccurs="0" maxOccurs="unbounded"/>  
       <xs:element ref="character" minOccurs="0" 
         maxOccurs="unbounded"/> 
     </xs:sequence> 
     <xs:attribute ref="id"/> 
     <xs:attribute ref="available"/> 
   </xs:complexType> 
 </xs:element> 
 <xs:element name="character"> 
   <xs:complexType> 
     <xs:sequence> 
       <xs:element ref="name"/> 
       <xs:element ref="born"/> 
       <xs:element ref="qualification"/> 
     </xs:sequence> 
     <xs:attribute ref="id"/> 
   </xs:complexType> 
 </xs:element> 

</xs:schema></source>