Thanks everybody,
I got my problem to work in one step less and using the Loader with the following:


create or replace trigger test_trigger before insert on table_a for each row
begin
select e into :new.b from table_b where d = :new.d;
end;
/


load data
infile *
append
into table system.table_a
FIELDS TERMINATED BY ","
(
a,
c,
d
)
begindata
...
...
...
...

One question though. How do I assign a specific rooback segment when executing the sql*loader?

Thanks once again
manjunath