XML/XML Schema/key

xsd:key

   <source lang="xml">

File: Data.xml <?xml version="1.0"?> <Party xmlns="http://www.wbex.ru"

                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                xsi:schemaLocation="http://www.wbex.ru Schema.xsd">
       <names>
           <Name><First>Peter</First><Last>Brown</Last></Name>
           <Name><First>Peter</First><Last>Costello</Last></Name>
       </names>

</Party>

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

           targetNamespace="http://www.wbex.ru"
           xmlns="http://www.wbex.ru"
           xmlns:reunion="http://www.wbex.ru"
           elementFormDefault="qualified">
   <xsd:element name="Party">
       <xsd:complexType>
            <xsd:sequence>
                <xsd:element name="names">
                    <xsd:complexType>
                        <xsd:sequence>
                            <xsd:element name="Name" minOccurs="0" maxOccurs="unbounded">
                                <xsd:complexType>
                                    <xsd:sequence>
                                        <xsd:element name="First" type="xsd:string"/>
                                        <xsd:element name="Last" type="xsd:string"/>
                                    </xsd:sequence>
                                 </xsd:complexType>
                            </xsd:element>
                        </xsd:sequence>
                    </xsd:complexType>
                </xsd:element>
           </xsd:sequence>
       </xsd:complexType>
       <xsd:key name="PK">
           <xsd:selector xpath="reunion:names/reunion:Name"/>
           <xsd:field xpath="reunion:First"/>
           <xsd:field xpath="reunion:Last"/>
       </xsd:key>
   </xsd:element>

</xsd:schema>

</source>