-- Динамическое получение название таблицы
DROP FUNCTION get_bill_couses_part_name(timestamp without time zone);
CREATE OR REPLACE FUNCTION get_bill_couses_part_name(created_at timestamp without time zone)
  RETURNS character varying AS
$BODY$
declare
  _part_from character varying;
  _part_to character varying;
  _table_name character varying;
begin
  _part_from := to_char((date_trunc('MONTH', created_at::date))::date, 'YYYY_MM_DD');
  _part_to := to_char((date_trunc('MONTH', created_at::date) + INTERVAL '1 MONTH - 1 day')::date, 'YYYY_MM_DD');
  _table_name := 'bill.bill_courses_' || _part_from || '_' || _part_to;
  return _table_name;
end;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
ALTER FUNCTION get_bill_couses_part_name(timestamp without time zone)
  OWNER TO developer;
GRANT EXECUTE ON FUNCTION get_bill_couses_part_name(timestamp without time zone) TO developer;


-- Триггер


CREATE OR REPLACE FUNCTION bill_courses_partition_create_function()
RETURNS TRIGGER AS
$BODY$
BEGIN
  IF (NEW.created_at >= '2016-11-01 00:00:00'::timestamp without time zone AND NEW.created_at < '2019-02-01 00:00:00'::timestamp without time zone) THEN
    EXECUTE format('INSERT INTO %s SELECT ($1).*', get_bill_couses_part_name(NEW.created_at::timestamp without time zone)) USING NEW;
  ELSE
    RAISE EXCEPTION 'Date out of range, probably child table is missing';
  END IF;
  RETURN NULL;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION bill_courses_partition_create_function()
OWNER TO developer;