Statement level transactions

Hi,

With the introduction of checkpoints, it is now possible (or has been
made very easy) to implement behaviour what Oracle calls "statement
level transaction". E.g:

Inserting an already existing value into a column with unique key
constraint throws an exception, but the containing transaction can
continue. I can mimique this behaviour by using checkpoints.

Is there any facility in place (in the JDBC driver or in the backend)
that already does this for me? I.e. is there a config parameter that I
have just to turn on to have statement level transaction behaviour?

I also remember having read in the new features list for 8.0 the
introduction of nested transaction. I found no mention to nested
transactions in the user guides though. Am I missing something?

Thank you!

Regards,
Peter