WSDL

One of the most important things kiddy noticed when she was reading about webservices is WSDL .So here's what managed to get inside kiddy's head :)

WSDL is Web Service Description Language which based on XML.It is platform and language independent.

A WSDL document describes a webservice. Using this description client can locate a webservice and invoke its available functions.This Document consists of several parts which describe a webservice.

• port type : describes a web service,define a group of operations that it can be performed
• message  : message parameter or message return values[data being communicated]
• types       : data types that are used by the web service
• binding    : provides specific details on how a port type operations will actually be transmittered over     the wire[via HTTP Get, HTTP Post or SOAP]

WSDL supports four basic patterns of operation such as,

• one-way
• request-response
• solicit-response
• notification

Following diagram illustrates above mentioned operation patterns

In brief, WSDL represent a contract between service request[client] and service provider[web server]which enables individuals or businesses to access services offered by other businesses.

Reference

http://msdn.microsoft.com/en-us/library/ms996486.aspx

http://oreilly.com/catalog/webservess/chapter/ch06.html