PostgreSQL - Generador ID o Cedulas Aleatorias

CREATE OR REPLACE FUNCTION generador.cedula_aleatoria()

  RETURNS character varying AS

$BODY$DECLARE o_codigo varchar;

BEGIN

	SELECT INTO o_codigo generador.get_random_number(9999999,20000000)   ;

	return o_codigo;

END;$BODY$

  LANGUAGE plpgsql VOLATILE

  COST 100;

ALTER FUNCTION generador.cedula_aleatoria()

  OWNER TO postgres;