Where did you add DB commit?
I'm regularly writing DI jobs updating/inserting into Oracle tables and I never set a explicit commit.
I run already into issues when I executed the code via a session (i.e. in the DIS code window). It always worked when I executed the same code in batch (I had so far never the time to investigate why I observed these differences in behaviour between executing code in a session or in batch but it might well be caused by a missing commit).
Looking at the code passed to the DBMS I always assumed that the commit is given implicit after the execute block ends.
If you're having issues then may be autocommit might help you:
http://support.sas.com/onlinedoc/913/getDoc/en/acreldb.hlp/a001371521.htm
Or you could use dbcommit=0 - but read the doku as there are some backdraws with where clauses.
HTH
Patrick