postgresql7.1
select rel_constraint__violation(:rel_id)
select case when exists
(select 1 from rc_violations_by_removing_rel r where r.rel_id = :rel_id)
then 1 else 0 end
select case when exists
(select 1 from rc_valid_rel_types r
where r.group_id = :group_id
and r.rel_type = :rel_type)
then 1 else 0 end