WSDL Documents: "WSDL Messages
The element defines the data elements of an operation.
Each message can consist of one or more parts. The parts can be compared to the parameters of a function call in a traditional programming language.
WSDL Types
The element defines the data types that are used by the web service.
For maximum platform neutrality, WSDL uses XML Schema syntax to define data types.
WSDL Bindings
The element defines the message format and protocol details for each port."
