One thing that we don't show in the basic JPA/EJB 3/JSF/ADF Faces tutorial for 11g is how to do an update or an insert into the database.
(We do show how to do an update in the cue cards tutorial).
As a fast solution to a question that poped up on OTN about this I created this short demo that shows you how to do this - all of course without a single line of code.
I'm just using default JPA entity on the Departments table, and the default session facade EJB that JDeveloper created for it. Then using the ADF binding layer to create the page that will let you do insert and updates.