Communicating Query: Where XQuery Fits and How to Implement It

XML Query (also known as XQuery) is now a W3C Recommendation, as of January 2007; in other words, it is recognised by governments and others as an international standard. There are many implementations, and already XQuery is being used in industry. Among the implementations certain patterns have emerged: sets of features, positioning, maturity and more. This paper is intended as an introduction not to XQuery but to talking about XQuery with potential users: it introduces a vocabulary, suggests a simple taxonomy of implementations based on the emergent patterns, and gives ways to help people choose from among those implementations, whether Free, open source or closed. Products and specific implementations are mentioned by name in this paper in order to give specific examples. This is not in any way an endorsement of those products: the author of this paper has no information about the reader's situation. One might reasonably assume that every implementation is good for something, even where it is not immediately clear what. An implementation that is weak in one area might be strong in another. A consultant might find that this paper provides useful ways to communicate with a client about how to use XQuery, and how to choose software. A programmer or query writer might also find it useful to have a wider perspective on how XQuery is used; an implementer might like to consider the scenarios given in the paper as possible features for the future. Communicating Query: Where XQuery Fits and How to Implement It Table of