Getting Started with Hibernate 3

Generate the Database Schema

You’ll be happy to learn that creating database tables from the mapping is a very similar process. As with code generation, you’ve already done most of the work in coming up with the mapping document. All that’s left is to set up and run the schema-generation tool.

The first step is something we alluded to earlier. We need to tell Hibernate the database we’re going to be using, so it knows the specific “dialect” of SQL to use. SQL is a standard, yes, but every database goes beyond it in certain directions and has a specific set of features and limitations that affect real-life applications. To cope with this reality, Hibernate provides a set of classes that encapsulate the unique features of common database environments, in the package org.hibernate.dialect. You just need to tell it which one you want to use. (And if you want to work with a database that isn’t yet supported “out of the box,” you can implement your own dialect.)

In our case, we’re working with HSQLDB, so we want to use HSQLDialect. The easiest way to configure Hibernate is to create a properties file named hibernate.properties and put it at the root level in the class path. Create this file at the top level of your src directory, with the content shown in Example 5.

Example 5. Setting up hibernate.properties

hibernate.dialect=org.hibernate.dialect.HSQLDialect hibernate.connection.driver_class=org.hsqldb.jdbcDriver hibernate.connection.url=jdbc:hsqldb:data/music hibernate.connection.username=sa ...