declare
        v_rec   record;
begin

        -- 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 = old.rel_segment 
                        and rel_side = old.rel_side
        LOOP

                delete from rc_segment_required_seg_map
                      where rel_segment = v_rec.rel_segment
                        and rel_side = old.rel_side
                        and required_rel_segment 
                            in (select required_rel_segment
                                  from rc_segment_required_seg_map
                                 where rel_segment = old.rel_segment
                                   and rel_side = old.rel_side);
                
        end LOOP;

        -- delete dependencies

        delete from rc_segment_required_seg_map
              where rel_segment = old.rel_segment
                and rel_side = old.rel_side
                and required_rel_segment 
                    in (select required_rel_segment
                          from rc_segment_required_seg_map
                         where rel_segment = old.required_rel_segment
                           and rel_side = old.rel_side);

        -- delete the constraint

        delete from rc_segment_required_seg_map
              where rel_segment = old.rel_segment
                and rel_side = old.rel_side 
                and required_rel_segment = old.required_rel_segment;

        return old;

end;