W3C XML Schema (WXS)

Express the grammatical rules for an XML vocabulary

W3C XML Schema (WXS), a grammar-based XML schema language, is used to define and limit XML vocabularies. It is the foundation of some other standards in areas from XML messaging to data binding. Learn about its relationship to other schema language technologies.

Contributors:  W3C

25 April 2007 (First published 06 February 2007)

W3C XML Schema (WXS), a grammar-based XML schema language, is used to define and limit XML vocabularies. It is the foundation of some other standards in areas from XML messaging to data binding. Learn about its relationship to other schema language technologies.

XML Schema Part 1: Structures Second Edition and XML Schema Part 2: Datatypes Second Edition [W3C Recommendations] define another schema language for XML. The first part allows you to constrain the structure of the document, and the second part allows you to constrain the contents of simple elements and attributes. WXS has faced criticism for complexity and a lack of expressiveness; the result is competition from other languages such as RELAX NG. Increasingly, people are just using whatever schema language suits them best and turning to an impressive crop of emerging tools to convert from one form to another according to need. Many other specifications have used the WXS Datatypes specification, although there have been calls to develop alternative data type systems. The working group has started work on WXS 1.1 -- XML Schema 1.1 Part 1: Structures and XML Schema 1.1 Part 2: Datatypes [in development]. These look to fix some of the much-reported problems with the 1.0 versions while retaining maximum backward compatibility.

Work is also winding down on Basic XML Schema Patterns for Databinding Version 1.0 [in development], which provides Schema usage advice for users of data binding systems. Data binding is a method of converting XML instances into application objects of a certain structure, and vice versa.

Resources

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