<?xml version="1.0" encoding="UTF-8"?>

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
   
   
    <xsd:simpleType name="albumIDType">
    <xsd:restriction base="xsd:ID">
    <xsd:pattern value="JW\d{6}" />
   </xsd:restriction>
  </xsd:simpleType>
 
 <xsd:simpleType name="jazzType">
  <xsd:restriction base="xsd:string">
    <xsd:enumeration value="New Orleans" />
    <xsd:enumeration value="Swing" />
    <xsd:enumeration value="Bebop" />
    <xsd:enumeration value="Modern" />
  </xsd:restriction>  
 </xsd:simpleType> 
                          
 			<xsd:element name="inventory">
   				<xsd:complexType>
    				<xsd:sequence>
      					<xsd:element name="album" minOccurs="1" maxOccurs="unbounded">
       						<xsd:complexType>
         						<xsd:sequence>								        															 
           								<xsd:element name="title" type="xsd:string" />
           								<xsd:element name="artist" type="xsd:string" minOccurs="1" maxOccurs="unbounded"/>									
           								<xsd:element name="tracks">
             								<xsd:complexType>
			 									<xsd:sequence>
         											<xsd:element name="track" minOccurs="1" maxOccurs="unbounded">
	          											<xsd:complexType>
															<xsd:simpleContent>																 
		            												<xsd:extension base="xsd:string">
	                  													<xsd:attribute name="length" type="xsd:time" default="optional" />																		
		            												</xsd:extension>															
		            										</xsd:simpleContent>		  	
	          											</xsd:complexType>
	           										 </xsd:element>	
												</xsd:sequence>
										      <xsd:attribute name="length" type="xsd:time" default="optional" />																								
										  </xsd:complexType>
									   </xsd:element>  
								 </xsd:sequence>															  
							 <xsd:attribute name="category" type="jazzType" use="required" />
      						 <xsd:attribute name="albumID" type="albumIDType" use="required" />									 	     
						</xsd:complexType> 
				     </xsd:element>
				  </xsd:sequence>	
			    </xsd:complexType> 
			 </xsd:element>				
	     </xsd:schema> 


