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Core Technologies for Web Services
Oracle's Siebel Web services use industry standard core technologies. The following topics provide an overview of each main core technology:
About Web Services Description Language (WSDL)
WSDL is an XML-based format for describing the interface of a Web service. WSDL describes the endpoints, location, protocol binding, operations, parameters, and data types of all aspects of a Web service:
- The WSDL which describes a Web service has the following characteristics:
- It is published by the service provider.
- It is used by the client to format requests and interpret responses.
- It can be optionally submitted to a registry or service broker to advertise a service.
- Additionally, WSDL describes the following:
- The operations provided by a Web service.
- The input and output message structures for each Web service operation.
- The mechanism to contact the Web service.
About XML and XML Schema
A WSDL file is published in the form of an XML document instance. Document or Literal is required as part of the WS-I interoperability standard that forms the basis of modern Web service usage, where:
- Document means that the payload for an operation, however complex, must be defined in a single XML element.
- Literal means that the definition of that element must be described by an XML Schema embedded in the WSDL file.
When using Document/Literal formatting, the WDL file will contain an XML Schema definition that defines all messages and data types that will be used for a particular service. The payload itself will consist entirely of XML data structures.
About Simple Object Access Protocol (SOAP)
SOAP is a lightweight protocol intended for exchanging structured information in a decentralized, distributed environment. SOAP uses XML to define an extensible messaging framework.
SOAP messages consist of the following:
- An envelope for wrapping messages, including addressing and security information.
- A set of serialized rules for encoding data types in XML.
- Conventions for a procedure call and, or response.