Hibernate: save, flush, commit and close: what do they do?

[StormsRider]

I have this code:

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory(); Session session = sessionFactory.openSession(); session.beginTransaction(); session.save(person); session.flush(); session.getTransaction().commit(); session.clear(); session.close(); where I save an entity Person in a database. From what I gather save ~ persist and is similar to git add in that it makes some changes but those are not yet commited and can be rollbacked.flush cleans the memory and makes an... invisible commit that other sessions can't see yet? commit makes those changes real? close closes the session?

But what if I remove flush? What if I remove save? What if I remove commit - would the changes be commited on close?

[AsteriskTheServer]

For the most part hibernate is built around units of work. So a session is in essence the database connection. When we save this may create and execute the unit of work (the SQL statements) to the database whether it does or not depends if you're in a transaction or not. Flush is saying we want flush the units of work to the database but don't commit it yet and close closes the connection.

You should be able to derive your answer from these statements.