Dear java.enterprise

I am very very knew to EJB, so I apoligize for my dumb questions. As I
understand it from reading through the introduction to EJB from jGuru at
the EJB container can save a beans properties as a record in a database
table (Container-managed persistence). How is this done? Can the EJB
container create the table if there is a knew bean wanting to save it
self into a database not already represented by a database table? If you
want to recreate a previously saved bean can you then use ordinary sql
the retrieve the beans you want to recreate or can it only be done
through the beans id? Do you have a pure javaframework to search for and
retrieve beans from the database without using sql? If so, how is this
done? Can Container-managed persistence substitute explicit use of JDBC
and RDB, so all persistence of beans and data is done through the use of
Container-managed persistence or have I completely missed the point

When the EJB introducion mention it takes care of transactions is it
then in the sense of databases. I mean, does it means that if a saving
process is not successful is the process then rolled back? What does it
means that the EJB container takes care of security. Does it mean that
outsiders can not hack into the system so that only clients has access
to the data. Can anyone mention an example on a security issue f.ex. in
money transactions which can benefit from the use of EJB.

Sincerely yours