Question

I couldn’t find a reference on how to switch hbm2ddl off.

Answer 1

Just omitting hibernate.hbm2ddl.auto defaults to Hibernate not doing anything. From the reference documentation:

1.1.4. Hibernate configuration

The hbm2ddl.auto option turns on
automatic generation of database
schemas directly into the database.
This can also be turned off by removing the configuration option,
or redirected to a file with the help
of the SchemaExport Ant task.

Setting hbm2ddl.auto to none (undocumented) might generate a warning, such as: org.hibernate.cfg.SettingsFactory - Unrecognized value for "hibernate.hbm2ddl.auto": none