Chapter 9. Persistence Tutorial

This chapter presents a tutorial for using the persistence system. It presumes you are familiar with the concepts covered in Chapter 2 WAF Component: Persistence.

This tutorial will first discuss using Data Objects, which is followed by a tutorial on using the features of PDL. Referenced throughout this tutorial is the Persistence Glossary.

9.1. Data Objects Tutorial

This section has been assembled to help familiarize you with the concepts and functionality of the persistence layer. This section assumes a familiarity with the concepts discussed in Chapter 2 WAF Component: Persistence and in Persistence Glossary. It also assumes that the code is being executed within a standard WAF installation.

This tutorial will walk you through the use of object persistence in the WAF. It begins by showing you how to ensure that your server is set up correctly so that the PDL will compile. It then continues with a simple example of how to create a PDL file and how to write the corresponding Java code to interact with the database.

After covering the basics of using standalone Data Objects, the tutorial describes how to associate objects to each other. It discusses several examples, including how to retrieve Data Objects through arbitrary queries. The tutorial concludes with a list of common mistakes that are made by developers.