
416 • XML & Related Technologies
We can see that the WSDL file is also an XML document. What is its significance? Figure 9.8 summarises
the main aspects of a WSDL file.
Element Usage
<portType>
Defines the abstract operations that the Web Service can
perform. It possibly has input, output, and fault sub-elements.
<operation> Specifies the operations supported by the Web Service.
<message>
Specifies the message details (request and response) needed
or returned by the Web Service.
<types> Specifies the data types used by the Web Service.
<binding>
Binds the Web Service to concrete communication protocols
and data format for a particular portType.
<service> ...