Transaction Managment DB2/400

When I say transaction management, I mean:

Start a unit of work-->perform work-->check for errors (if none
found)-->commit work (else, rollback to start).

I'm hoping the list can provide me with two things.

1) a good reference for reading the details of transaction management on
DB2/400. I started doing some research and found lots on isolation levels -
but that seems more about isolation of reads (whether reads can be dirty,
etc.) rather than enforcing change control. (please note that I am
primarily an MS SQL DBA/Developer so I may have gleaned something incorrect
from my reading).

2) a quick primer to get me started, for instance, the real code to perform
this:

BEGIN TRANSACTION

UPDATE table1
set foo = x, bar = y
WHERE col1 = Z;

IF NO ERROR RETURNED THEN
COMMIT;
ELSE
ROLLBACK;
END IF;

Thanks much. RH