XML —

A Schema for the Body Content of the SOAP Message

As you can see, we have not yet defined the NPO schema located at http://www.northwindtraders.com/schemas/NPOSchema.xsd. This schema can be defined as follows:

  <xsd:schema xmlns:xsd="http://www.w3.org/1999/XMLSchema"
     targetNamespace="http://schemas.xmlsoap.org/soap/envelope"
     xmlns:SOAP="http://schemas.xmlsoap.org/soap/envelope">
     <xsd:complexType name="NorthwindHeader">
        <xsd:element name="GUID" type="string"/>
     </xsd:complexType>
     <xsd:complexType name="NorthwindBody">
        <xsd:element name="UpdatePO">
           <xsd:complexType>
              <element name="orderID" type="integer"/>
              <element name="customerNumber" type="integer"/>
              <element name="item" type="double"/>
              <element name="quantity" type="double"/>
           </xsd:complexType>
        </xsd:element>
     </xsd:complexType>
  </xsd:schema>

This schema creates two elements: NorthwindBody and NorthwindHeader. Using the xsi:type attribute, we can extend the SOAP body element with the NorthwindBody complex type and extend the Header element with NorthwindHeader complex type. You can then create the following SOAP document:

  <SOAP-ENV:Envelope
     xmlns:xsi="http://www.w3.org/1999/XMLSchema/instance"
     xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope"
     xsi:schemaLocation=
        "http://www.northwindtraders.com/schemas/NPOSchema.xsd">
  <SOAP-ENV:Header xsi:type="NorthwindHeader">
        <COM:GUID xmlns:COM="http://comobject.northwindtraders.com">
           10000000-0000-abcd-0000-000000000001
        </COM:GUID>
     </SOAP-ENV:Header>
     <SOAP-ENV:Body xsi:type="NorthwindBody">
        <UpdatePO>
           <orderID>0</orderID>
           <customerNumber>999</customerNumber>
           <item>89</item>
           <quantity>3000</quantity>
        </UpdatePO>
     </SOAP-ENV:Body>
  </SOAP-ENV:Envelope>