declare
        v_rec   record;
begin
        -- insert the constraint

        insert into rc_segment_required_seg_map
               (rel_segment, rel_side, required_rel_segment)
               values
               (new.rel_segment, new.rel_side, new.required_rel_segment);

        -- add dependencies

        insert into rc_segment_required_seg_map
             select new.rel_segment, new.rel_side, required_rel_segment
               from rc_segment_required_seg_map
              where rel_segment = new.required_rel_segment
                and rel_side = new.rel_side;

        -- now update the rel_segments that depend on this segment
        
        for v_rec in select rel_segment 
                       from rc_segment_required_seg_map
                      where required_rel_segment = new.rel_segment 
                        and rel_side = new.rel_side
        LOOP
                insert into rc_segment_required_seg_map
                     select v_rec.rel_segment, new.rel_side, 
                            required_rel_segment
                       from rc_segment_required_seg_map
                      where rel_segment = new.rel_segment
                        and rel_side = new.rel_side;
                
        end LOOP;

        return new;

end;