I have troubles with transactions in Oracle. I have some procedures like this:
create or replace procedure myschema.DataSave(v_value IN NUMBER)
as
begin
SET
Oracle doesn't support nested transactions. If a transaction commits, it commits. That's why you generally don't want to commit (or rollback) a transaction in a stored procedure, that makes it difficult to reuse the procedure elsewhere if your transaction semantics differ.
You can, however, declare a savepoint at the beginning of your procedure and rollback to that savepoint in the case of an error. If you then remove the commit, then the transaction is solely controlled by the application code not by the database code
begin
savepoint beginning_of_proc;
insert/update/delete...
exception
when OTHERS then
rollback to beginning_of_proc;
raise;
end;
In this case, though, my bias would be not to have a savepoint in the code, not to have a rollback, and not to catch the exception unless you're doing something useful with it. Just do the DML, let any exceptions get thrown, and handle them in your application.