--
-- timespan__delete/1
--
create or replace function timespan__delete(
  integer
) returns int4 as $$

declare
       delete__timespan_id alias for $1; 
begin
       -- Delete intervals, corresponding timespan entries deleted by
       -- cascading constraints

       delete from time_intervals
       where  interval_id in (select interval_id
                              from   timespans
                              where  timespan_id = delete__timespan_id);
       return 0;

end;$$ language plpgsql;