Hello, I am a newbie in Hibernate concepts.

I want to build my system using JPA+Hibernate, my question is:

What is the best approach, mapping from tables to classes or vice versa?

In other projects in which I have worked , database script was already created, for that reason I mapped from tables to objects, but in this case there isn´t any script.

Which are advantages/disadvantajes from each one? Which would you recommend?

Thanks in advance.