<?xml version="1.0" encoding="utf-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
   <xs:element name="name" type="xs:token"/>
   <xs:element name="first-name" type="xs:token"/>
   <xs:element name="middle-name" type="xs:token"/>
   <xs:element name="last-name" type="xs:token"/>
   <xs:element name="qualification" type="xs:token"/>
   <xs:element name="born" type="xs:date"/>
   <xs:element name="dead" type="xs:date"/>
   <xs:element name="isbn" type="xs:integer"/>
   <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:token">
               <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:choice>
               <xs:element ref="name"/>
               <xs:sequence>
                  <xs:element ref="first-name"/>
                  <xs:element ref="middle-name" minOccurs="0"/>
                  <xs:element ref="last-name"/>
               </xs:sequence>
            </xs:choice>
            <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:choice>
               <xs:element ref="name"/>
               <xs:sequence>
                  <xs:element ref="first-name"/>
                  <xs:element ref="middle-name" minOccurs="0"/>
                  <xs:element ref="last-name"/>
               </xs:sequence>
            </xs:choice>
            <xs:element ref="born"/>
            <xs:element ref="qualification"/>
         </xs:sequence>
         <xs:attribute ref="id"/>
      </xs:complexType>
   </xs:element>
</xs:schema>

