WSDL Full Form

WSDL stands for Web Services Description Language. It was developed jointly by IBM and Microsoft and recommended on June 26′ 2007 by the W3C. Written in XML, it is used in describing web services. These descriptions include service location and methods. It works in coordination with SOAP and UDDI in order to provide web services, i.e SOAP is used to call web services that are listed in WSDL. Generally, a typical WSDL contains information about definition, datatypes, messages, service, bindings, targetNamespace, and port type. Prerequisites for learning about WSDL is basic XML schema and namespaces.  

Characteristics 

• It specifies the operations that will be performed by the web services and how these services must be accessed.
• It is based on the XML protocol used for exchanging information in distributed systems.
• It describes the specifications to be met for interfacing with XML oriented services.
• WSDL works combinedly with SOAP and UDDI.

Advantages

• It provides a systematic approach to defining web services. 
• Used to reduced the total LOC which is must to access the web services. 
• It can be updated dynamically which allows the users to seamlessly upgrade to new patterns. 

Disadvantages 

• Single mode (one-way) messaging is prohibited. 
• It cannot include more than one file i.e cannot have more than one <wsdl:include> element. 
• It does not support output mapping.