I have to agree with Davey.
I'd like to do coding more from server.
forget odbc/ole db.
OCI/OCCI for C/C++ will take more development time due to referrences. But that's depends on the expertise of your developers.
If I were to make a choice, I will prefer JDBC and Java.
Due to reasons like portability of codes, referrences, performance is considerable, ease of maintenance after implemented(not much bugs to occur) and it's the IN thing for me in the development circle right now. But that's just me.
I don't see why waiting for commits is going to prevent you from reaching that target -- commit is extremely fast in Oracle. It seems an odd thing to focus on -- I'd be thinking more about the need to use low latency connections and bulk binding.
Like davey says, which ones do you know about? And where are you going to place your logic? If you want to reduce roundtrips to the database then put your logic into PL/SQL packages and call them with OCI.