 | Level: Intermediate Nicholas Chase (ibmquestions@nicholaschase.com), Freelance writer, Backstop Media
Tracy Peterson (tracy@tracypeterson.com), Writer, Freelance
05 Sep 2006
Updated 08 Mar 2007 The many massive applications that you use day to day for search, online shopping or to find your way around town provide data for your use in a completely new application. Enterprising application developers have created many mashup applications to coax a specific purpose out of the combination of several applications' data sets. Part 1 of this series discussed an application, which begins to draw data from several services and combines it. Now we will discuss how to save request results to a DB2 9 database, plus take some of the load off of those external services and improve performance dramatically.
In this tutorial
The purpose of this tutorial series is to create a mashup application so smart that users can literally add and remove services at will, and the system will know what to do with them. The series progresses as follows: -
Part 1: The author introduces the concept of mashups and how they work. You then build a simple version of one and also discover serious performance problems involved in making potentially dozens of Web calls.
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Part 2: You solve some of that problem by using DB2's new pureXML capabilities to build an XML cache, which saves the results of previous requests and also enables you to retrieve specific information.
- Parts 3, 4, and 5: Ultimately, you will need to use ontologies, or vocabularies that define concepts and their relationships, so in Part 3 you start that process by learning about RDF and RDFs, two key ingredients in the Web Ontology Language (OWL), which the author discusses in Part 4. In Part 5, you take the ontologies created in Part 4 and use them to enable users to change out information sources.
- Part 6: At this point, you have a working application and the framework in place so that the system can use semantic reasoning to understand the services at its disposal. In this part, you give the user control, enabling him or her to map new services into the ontology and to pick and choose the data that is used for a custom mashup.
Over the course of this tutorial, you will learn how to set up a database server and prepare it to receive the data that you collect as well as how to write the queries needed to specifically handle XML data in an XML column. This tutorial uses the Java language, but the concepts are the same for any programming language or operating system.
Objectives - Set up DB2 Enterprise Edition
- Create a new DB2 9 database which is configured to handle XML
- Create a database table using the XML column type
- Select information stored as XML in a relational database using XPath
- Write XQuery XML queries
- Write hybrid SQL and XQuery queries
Prerequisites
This tutorial is for developers who want to learn how to use and combine Web services from the XML point of view, and to output that data to the Web. It assumes that you are familiar with Java™, XML, SQL, Web development and the basic concepts of Web services. Familiarity with JDBC will be helpful. If you need a refresher on these topics, please see the Resources listed in the tutorial for more information.
System requirements
You will need JavaScript enabled in your browser. To follow along with the code in this tutorial, you will need to have the following software installed and tested.
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IBM® DB2® 9 (formerly known as "Viper"): This relational database also includes significant XML capabilities, which you'll need for this tutorial. You can download a trial version of DB2 9: DB2 Enterprise 9 or DB2 Express-C 9, a no-charge version of DB2 Express 9 data server.
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Apache Tomcat or other servlet engine: This tutorial assumes that you will build Web applications using servlets, so you'll need a servlet engine such as Apache Tomcat. If you choose to build the application using another environment, just make sure you have the appropriate software on hand. Download apache-tomcat-5.5.17.zip and install into a directory with no spaces in the directory name.
- Java: Apache Tomcat 5.5, with which this tutorial is built, requires Java 1.5 or higher. Download the J2SE SDK.
- To make things easier, you can use an IDE such as Eclipse or IBM Rational™ Web Developer for your development. You can download Eclipse at Eclipse.org, download a trial version of Rational Web Developer, or use your favorite development environment. You won't be doing anything fancy as far as compilation and deployment are concerned.
Duration
2 hours
Formats html, pdf
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