About XQuery

XQuery is a query language for XML. It is developed within the W3C by the XML Query Working Group, as part of the XML Activity. XQuery is a simple but powerful language that supports a large variety of data-oriented and document-oriented XML applications. From 1000 feet, the salient features of XQuery are:

• The ability to write clearly and concisely advanced manipulation/transformation of XML data.
• A declarative approach that promotes optimization and efficient implementations.
• A type system that takes advantage of schema descriptions and enables early detection of errors in programs.

High-level requirements for XQuery can be found in the XML Query Requirements Documents.

Many applications and XQuery examples can be found in the XML Query Use Cases.

More information on XQuery, and the W3C XML Query Working Group, can be found on the W3C XML Query homepage.

About Galax

What is Galax?

Galax is an open-source implementation of XQuery. Our goal is for Galax to be a fully compliant implementation of the family of XQuery working drafts. Galax implements the following specifications from the XML Query Working Group:

• XQuery 1.0: An XML Query Language
• XML Path Language (XPath 2.0)
• XQuery 1.0 and XPath 2.0 Data Model
• XQuery 1.0 and XPath 2.0 Functions & Operators
• XQuery 1.0 Formal Semantics
• XQuery Update Facility 1.0
• XQuery Scripting Extension 1.0

Galax does not currently support XQueryX, the XML syntax for XQuery. It is still based on the January 2007 W3C Recommendations, and does not include fixes listed in the Errata for XQuery 1.0 document, or the more recent XQuery 1.1.

Who should use Galax?

Galax is a portable and extensible implementation of XQuery, with a liberal open-source license which makes it ideal for:

• XQuery users who want to learn the language and try queries on a light-weight, portable system;
• Students and researcher who want to experiments with an XQuery implementation;
• XML application developers who need a lightweight, easily embeddable, XQuery engine for their application;
• Implementors of XQuery systems who want to understand, or get access, to the internals of an XQuery engine.
• Anybody who needs a statically typed implementation of XQuery.

The Galax Team, past and present.

Project Lead

• Mary Fernández, AT&T Labs Research.
• Jérôme Siméon, IBM T.J. Watson Research Center.

Contributors

• Cindy Chen, University of Massachusetts at Lowell.
• Byron Choi, Hong Kong Baptist University.
• Vladimir Gapeyev.
• Trevor Jim, AT&T Labs Research.
• Amélie Marian, Rutgers University.
• Philippe Michiels.
• Kristi Morton, University of Washington.
• Nicola Onose, UC Irvine.
• Douglas Petkanics.
• Christopher Rath, AT&T Labs Research.
• Christopher Ré, University of Wisconsin-Madison.
• Michael Stark.
• Gargi Sur, Google.
• Avinash Vyas, Bell Laboratories.
• Philip Wadler, University of Edinburgh.

Acknowledgments

We would like to extend our thanks to:

• To Arnaud Sahuguet for the Galax logo.
• To the members of the XML Query Working Group, notably Peter Fankhauser, who contributed ideas and suggestions.
• To the XDuce team, notably Haruo Hosoya, for discussions and for allowing us to use their subtyping algorithm at the early stages of our implementation.
• To the Caml team for developing the best programming language in the world.