oracle8.1.6
insert into cu_user_element_map
(user_id, element_id, curriculum_id, package_id, completion_date)
select :user_id,
:element_id,
:curriculum_id,
:package_id,
sysdate
from dual
where not exists
(select 1 from cu_user_element_map
where user_id = :user_id
and element_id = :element_id)