XQuery

Definition

Xquery, XML Query Language, is a query language that uses the structure of XML intelligently can express queries across all these kinds of data, whether physically stored in XML or viewed as XML via middleware. In other words, you can use it to retrieve things from files, from XML representations made from SQL databases, from native XML databases like eXist. In addition, Xquery is quite a real programming language.

Xqupdate, (XQuery Update Facility) is a recent (2007) language for updating xml data. There is an older proposal, XUpdate

See also XML databases, servers in which you can plug XML "as is" and get it back with Xquery. Such DBMS also may support XPath, XSLT and other means.

This is just a page with links.

See XQuery tutorial - basics

Documentation

Standards

• XQuery 1.0: An XML Query Language (the central document). XQuery can only query (not update). There are some other parts, e.g.
  • XML Query Use Cases
  • XML Query Requirements
  • XML Query 1.0 and XPath 2.0 Data Model
  • XQuery 1.0 and XPath 2.0 Formal Semantics. Easy bedtime reading ;)
• XQuery 1.0 and XPath 2.0 Functions and Operators
• xqupdate - XQuery Update Facility. (W3C Working Draft 28 August 2007). As of nov 2007, there are not many implementations for this replacement of Xupdate.
• Xpath 2.0 is used both by XSLT 2.0 and XQuery. XQuery is an extension of XPath 2.0 and both XSLT 2.0 and XQuery 2.0 share the same data model.
• Xupdate. Not a W3C standard, can be used to update some XML databases (not updated since 2000 an will be replaced by XML Query Update). Xupdate looks a lot like XSLT.

XQuery Tutorials

See XQuery tutorial - basics !

• XQuery (Wikipedia article)

Other

• XML:DB XUpdate Use Cases by Kimbro Staken. This document outlines a basic set of uses cases for the XUpdate specification from the XML:DB Initiative.

Software

See also XQuery Engines, Processors, Providers at SQLSummit, retr. Jan 2010.

XML databases

See XML database

XQuery Engines

• XQuery Engines, Processors, Providers A list of products by SQL Summit.com

• SAXON XSLT and XQuery Processor. There is a free version. (works).
• XQEngine - XML Query Engine implements XQuery - sourceforge project.
• MXQuery. low-footprint, extensible XQuery Engine (Java). Includes support for update
• Galax. open-source implementation of XQuery 1.0.
• Safari Guide Safari Guide is a free application for Mac OS X Tiger that allows developers to evaluate arbitrary XPath and XQuery expressions against the current frontmost Safari webpage. [10/2005]
• XQuery USE ME (XqUSEme) Firefox add-on (based on Saxon-B, Java 1.6 update 12+ is needed)
• XQIB XQuery in the browser (IE / FF 3.5] (Feb 2010). Probably needs administrator rights to install, security is not guaranteed...

the error console while using the extension. All in all, a useful extension if you want to query information from documents on the web and are familiar with XQuery.

XML Editors with XQuery support

See XML editor for a list of XML editors

Many, e.g. XML Exchanger lite.

Libraries

For eXist

• PheXist is a set of classes for PHP 5. (older version also for PHP4 & Perl) to query and manipulate XML documents in eXist XML:DB. (Version 0.5, april 2007). PHP 5 needs the soap extension enabled.

PHP

• Zorba PHP extension for Zorba, an XQuery processor.

Examples

• MarkMail. Mailing list archive that stores messages in XML. Search (under the hood) is done with Xquery.

Links

• XML Database Products by Ronald Bourret