Embedded Database

Obtaining Database Information

Geronimo includes a built-in relational database. When you select Embedded DB→DB Info, menu, you will receive a screen full of information describing the embedded database.

The database is Apache Derby. It is a 100 percent Java, full-featured relational database that is originally based on code initially contributed by IBM. In fact, IBM continues to market a version of the database called Cloudscape.

Geronimo uses this embedded database as a system database. You can also use this database in your own application. Figure 8-19 shows the page displayed by Geronimo. It provides a lot of useful information on the embedded Derby instance.

Database Manager Portlet

The Database Manager portlet enables you to configure and work with the embedded database instance.

This database instance is used by some Geronimo system services such as ActiveMQ.

Using the database manager portlet, you can create new database instances, create new tables, and execute SQL against the embedded database instance. You can also view tables and their contents in both the application and (Derby) system databases.

Figure 8-20 shows the entry of a SQL CREATE TABLE statement to be executed on the embedded Derby instance.

Figure 8-20: Running SQL against the embedded database with Database Manager portlet