To undeploy the published services, delete the enterprise app archive from the deploy directory of your JBoss configuration.
To remove the process from the database, call
There is no preference at all. The stability and performance of a specific database depends on the JDBC driver and the Hibernate dialect. If you have a concrete issue that prevents you from using jBPM BPEL with a specific database, let us know.
Personally, I use MySQL when I want to test against a production database. It has a small footprint, comes with decent tools and fails with meaningful messages, if it fails at all. I know PostgreSQL is good, too.
In a previous life, I was fond of SQL Server when targeting Windows platforms. SQL Server 2000 JDBC drivers have a number of issues. Conversely, SQL Server 2005 drivers are much better; they even have Hibernate certification.
I guess Oracle is good, considering how expensive it is, but I can't say much about it.
I'm afraid that's all we got right now. Please tell us if you feel some area really needs deeper coverage.
Could you give me more information how to remove the process from the database, org.jbpm.db.GraphSession.deleteProcessDefinition()?