The documentation about the hibernate.hbm2ddl.auto property lists every possible values, but does not explain what they do.

I suggest providing a bullet list with a brief explanation about each possible value, focusing on these main questions:

• What will happen to existing data? Is hbm2ddl going to truncate existing tables?
• What will happen to existing tables? Is hbm2ddl going to drop existing tables?
• What will happen after the SessionFactory is closed?

My (incomplete) proposal:

Automatically validates or exports schema DDL to the database when the SessionFactory is created.

e.g. validate | update | create | create-drop

• validate: validates that the existing database schema matches your mapping documents. See http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html/ch21.html#toolsetguide-s1-8
• update: updates an existing schema with incremental changes. See http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html/ch21.html#toolsetguide-s1-6
• create: FIXME: I don't know how to answer to the above questions. See http://docs.jboss.org/hibernate/orm/4.3/manual/en-US/html/ch21.html#toolsetguide-s1-3
• create-drop: same as create, plus the database schema will be dropped when the SessionFactory is closed explicitly.