You choose the database server when you create a Ruby on Rails project in the New Project dialog (choose Files > New Project, then select Ruby in the Category list and New Ruby on Rails Application in the Projects list).
Using JRuby means that you have a number of choices in the NetBeans IDE for the database server. MySQL is the simplest to use because NetBeans Ruby supplies an adapter that you use just as you do in a native Ruby application. In addition, NetBeans supplies a JDBC 3.0 adapter, the ActiveRecord-JDBC gem, that can be used with a number of database drivers.
For the latest information on database support in NetBeans Ruby, see "Using Database Servers With JRuby" in
You do not need to register your database server with the IDE to use it from your Ruby project. However, if you do so, you can create and view tables and exercise SQL commands directly from the IDE. If you are using JavaDB, you do not need to register it. For more information, see "Registering Database Servers With the IDE" in
If you want to add a database, see "Adding Databases" in for instructions on some common databases.