Question

I would like to use hsql within my DAO unit tests for a web application. The web app is written against mysql and uses three different schemas within the same mysql database. Some schemas has FK relationships with data in the other schemas. If I’m to unit test, I must be able to execute against a database that can hold multiple schemas.

I know that HSQL supports multiple schemas, but I don’t know how to configure hsql to have multiple schemas set up for an in-memory database. I read that I can define multiple schemas in the server.properties file, but the file needs to be in the location of where the java class was called — the junit.jar location? If so, that would be hard to support in my Java Maven application. How can I:

1. Run an in-memory hsql database to start up with three databases?
2. Where would I place the server.properties file in my Maven app?
3. Could I point hsql to use a server.properties file in a location other than where the junit jar is (that’s a showstopper for me)?
4. Is it possible to configure multiple schemas for an in-memory database just via a tricked out jdbc url?

I wish I could untangle the schemas from each other, but that’s not possible at this time.

Thanks for your help!

Answer 1

HSQLDB supports multiple schemas in the same database. Foreign keys can reference tables from different schemas. The following apply to the very latest HSQLDB 2.2.6 snapshot available from http://hsqldb.org

1. Before running your tests, execute CREATE SCHEMA schemaname for each schema.
2. Doesn’t matter where, you can specify the absolute path on the command line arguments when running. See the HSQLD Guide and JavaDoc on server.
3. Yes.
4. No. You use the SQL statement to create the schemas.

Note you have two options for running HSQLDB, one is as a server, the other is as an embedded database. In the case of server, it must be started before the test run. In both cases, you need to connect to the database and create the schemas before your tests.