XML Query  - XML Query Language

XML Query operates on the abstract, logical structure of an XML document, rather than its surface syntax. This logical structure is known as the data model, which is defined in the XML Query 1.0 and XPath 2.0 Data Model document.

XML Query Version 1.0 is an extension of XPath Version 2.0. Any expression that is syntactically valid and executes successfully in both XPath 2.0 and XML Query 1.0 will return the same result in both languages. Since these languages are so closely related, their grammars and language descriptions are generated from a common source to ensure consistency, and the editors of these specifications work together closely.

XML Query also depends on and is closely related to the following specifications:

• The XML Query data model defines the information in an XML document that is available to an XML Query processor. The data model is defined in XML Query 1.0 and XPath 2.0 Data Model.
• The static and dynamic semantics of XML Query are formally defined in XML Query 1.0 and XPath 2.0 Formal Semantics. This document is useful for implementors and others who require a rigorous definition of XML Query.
• The type system of XML Query is based on Schema.
• The default library of functions and operators supported by XML Query is defined in XML Query 1.0 and XPath 2.0 Functions and Operators...
• One requirement in XML Query 1.0 Requirements is that an XML query language have both a human-readable syntax and an XML-based syntax. The XML-based syntax for XML Query is described in XML Query: An XML Query Language 1.0.

The current edition of XML Query 1.0. has not incorporated recent language changes; it will be made consistent with this document in its next edition.

This document specifies a grammar for XML Query, using the same Basic EBNF notation used in XML, except that grammar symbols always have initial capital letters. Unless otherwise noted, whitespace is not significant in the grammar. Grammar productions are introduced together with the features that they describe, and a complete grammar is also presented in the appendix (A XQuery Grammar).

Extrait de [ recommandation XQuery 3.0: An XML Query Language]