Now that you understand the data types, it’s time to consider how vendors implement these data types. The technique used implement the data type determines where the type definitions appear within the SOAP message. There are two common methods in use by most SOAP toolkit vendors now.
Define the data types as part of the elements in the SOAP message.
Define the data types as part of an external file that the listener or XML parser uses to decode the SOAP message.
Let’s begin by looking at the first method for defining data types. Many developers feel that using external files such as WSDL unnecessarily complicates what should be a simple protocol for exchanging data. Here’s a simple SOAP message that contains data ...