Semantic Annotation for WSDL and XML Schema Current Status

This page summarizes the relationships among specifications, whether they are finished standards or drafts. Below, each title links to the most recent version of a document.

Completed Work

W3C Recommendations have been reviewed by W3C Members, by software developers, and by other W3C groups and interested parties, and are endorsed by the Director as Web Standards. Learn more about the W3C Recommendation Track.

Group Notes are not standards and do not have the same level of W3C endorsement.



Semantic Annotations for WSDL and XML Schema

This document defines a set of extension attributes for the Web Services Description Language and XML Schema definition language that allows description of additional semantics of WSDL components. The specification defines how semantic annotation is accomplished using references to semantic models, e.g. ontologies. Semantic Annotations for WSDL and XML Schema (SAWSDL) does not specify a language for representing the semantic models. Instead it provides mechanisms by which concepts from the semantic models, typically defined outside the WSDL document, can be referenced from within WSDL and XML Schema components using annotations.

Group Notes


Semantic Annotations for WSDL and XML Schema — Usage Guide

Web services provide a standards-based foundation for exchanging information between distributed software systems. The W3C Recommendation Web Services Description Language (WSDL) specifies a standard way to describe the interfaces of a Web Service at a syntactic level and how to invoke it. While the syntactic descriptions provide information about the structure of input and output messages of an interface and about how to invoke the service, semantics are needed to describe what a Web service actual does. These semantics, when expressed in formal languages, disambiguate the description of Web services interfaces, paving the way for automatic discovery, composition and integration of software components. WSDL does not explicitly provide mechanisms to specify the semantics of a Web service. Semantic Annotations for WSDL and XML Schema (SAWSDL) defines mechanisms by which semantic annotations can be added to WSDL components. This usage guide is an accompanying document to SAWSDL specification. It presents examples illustrating how to associate semantic annotations with a Web service. These annotations could be used for classifying, discovering, matching, composing, and invoking Web services.

Some of the examples illustrated in this document use RDF and OWL Web Ontology Language for representing ontologies. Some knowledge of RDF and OWL is useful for understanding this document, but not essential.