Implementing XQuery 1.0

This chapter demonstrates the Galax system as well as its most advanced features, including support for XPath 2.0, XML Schema, and static type checking. It also presents some of the first experiments with optimization. The chapter demonstrates query-rewriting capabilities in the Galax compiler, and the ability to run queries on documents up to a Gigabyte without the need for preindexing. Although early versions of Galax have been shown in industrial conferences over the past, this is the first time it is demonstrated in the database community. Galax is a light-weight, portable, open-source implementation of XQuery 1.0. Started in December 2000 as a small prototype designed to test the XQuery static type system, Galax has now become a solid implementation, aiming at full conformance with the family of XQuery 1.0 specifications. Because of its completeness and open architecture, Galax also turns out to be a very convenient platform for researchers interested in experimenting with XQuery optimization.