Before you start

Before you examine XQuery code samples, here's how to get the most of this tutorial, and instructions on how to install and use the included source code (see Downloads).

About this tutorial

This tutorial is about using XQuery to develop applications and middleware. It outlines some of XQuery's limitations while you develop applications, gives you practical advice along the way on how to manage these limitations as well as highlights where XQuery makes it easy or difficult. The bulk of the tutorial then builds on these principles, as it presents a series of programmatic idioms commonly found in application development:

• Use of extension functions
• Unit testing and assertions
• Recursion and sorting
• Higher-order functions

Each section comes with accompanying source code examples (see Downloads).

Back to top

Objectives

The goal of this tutorial is to give you a practical grounding in how to develop applications with XQuery. I try to provide cut-and-paste code that you can re-use in your own application-development efforts, though it is my hope that these code examples will inspire you to reconsider using XQuery for more than querying XML.

Back to top

Prerequisites

This tutorial is written for developers who have a general familiarity with XML technologies as well as some cursory XSLT or Query experience. The programmatic idioms presented can be found in one form or another in a lot of computer programming languages, and I make no claim of invention on them. This re-use should mean that for most readers, you'll see familiar constructions—albeit set in the context of XQuery programming.

Back to top

System requirements

You must install Michael Kay's Saxon XSLT and XQuery processor SA aware version to execute code examples. As you need the Saxon-SA version, you must register for a 30-day trial (for example, at the time of this writing version 9.1SA was used in testing). Many of the code examples use higher-order functions to take advantage of specific Saxon-SA extension functions (specifically, the saxon:function()).

Place all the Java™ Archive (JAR) files and license file in Saxon under the /lib directory.

To run examples you can invoke Saxon from the command line or use the included Ant build file (which I used to test the code examples). If you do use the build file, then you should also install the latest Apache Ant, and take care to amend the saxon.lib.dir property to point to the /lib directory containing Saxon JARs. To test whether Saxon is working properly, run the Ant target checkSaxon, which will successfully process when Saxon is installed properly. All Ant targets generate result output into the /result directory.

1 of 10 | Next

Comments

Back to top

Table of contents

• Before you start
• Today's XQuery
• Using extension functions
• Unit testing and assertions
• Recursion and sorting
• Higher-order functions
• Summary
• Download
• Resources
• About the author

---

1 of 10 | Next

Next steps from IBM

With the no-charge DB2 Express-C, pureXML and evolving your XML schemas you can easily increase development and application performance.

---

• Try: Download a free trial version of DB2 Express-C, which includes pureXML technology that is ideally suited for managing XML schema and relational data.
• Article: See how to use DB2's pureXML schema evolution capabilities, that evolve schemas without making any changes to your applications.
• Tutorial: This tutorial shows you how using a native DB2 XML database enables changes in an existing XML schema to also appear in your application code.
• Demo: This demo shows you how easy it is to create a DB2 database for storing XML data.
• Buy: DB2 9 for Linux, UNIX and Windows

Dig deeper into XML on developerWorks

Try IBM PureSystems. No charge.

Experience today!

---

Get started with the cloud-based trial and pattern development kit.