How to manage a HSQLDB in JBoss AS7.1.x - entity

Question

It's my first try to use EJB3.1 entities with a JBoss AS7.1.1 server. I figured out that the HSQLDB is no longer included in the version 7 of JBoss. First I added the hsqldb.jar through the Administration Console --> Deployments --> Manage Deployments. After that I added a new Data Source through Profil --> Connector -> Datasources
My first example code works fine:
[...]
InitialContext ic = new InitialContext();
DataSource ds = (DataSource) ic.lookup("java:/DefaultDS");
con = ds.getConnection();
stmt = con.createStatement();
stmt.execute("drop table timers;");
stmt.execute("Create table timers(id char(10));");
stmt.execute("INSERT INTO timers (id) VALUES (20)");
stmt.execute("INSERT INTO timers (id) VALUES (21)");
ResultSet number = stmt.executeQuery("select * from timers");
[...]
My question is how I can manage (=create, drop and update new tables) the DB which is created in the folder jobss\standalone\data\hypersonic. At the moment I have no "overview" which tables are created, the structure of them and the data.
Does someone have a tip or a tutorial for me which deal with the problem? Thank you.

Answer 1

In my case it was easier as I thought at the beginning. I needed to manage the DB which is stored in the AS 7.1.x Server. Because of the missing JMX-Console I wasn't able to get access to that DB over the administration. I've added the Datasource and the Manage Deployments as described in the first post.
To manage such a DB you can use the 'HSQLDB Database Manager', select 'HSQL Database Engine Standalone' as the type and 'jdbc:hsqldb:file:«MY_PATH_TO_DB_FOLDER_IN_JBOSS»' for the URL. Now I can manage the DB outside the server and EJB environment.
Thanks you fredt for your help and your inspirations.

Answer 2

You always query INFORMATION_SCHEMA tables to find out which tables already exist. Once you know a table exists, you can execute a query that you know does not take a long time, in order to find out about the state of the data.
For example, the first query will show you if there is a 'TIMERS' table, and the second query will show if there is any data in the table:
SELECT * FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_NAME = 'TIMERS'
SELECT * FROM TIMERS LIMIT 1
Try always to define a primary key on each table in order to speed up queries.
To access a database embedded in an app server, you should add the org.hsqldb.server.Servlet class as a servlet then connect to the app server using a database management tool and a URL such as jdbc:hsqldb:http:<your servlet url here>