PROCEDURE hr.regexp_demo
   ( v_s IN varchar2)
   IS
BEGIN
 if  REGEXP_LIKE(v_s, '^[[:alpha:]]{3}_') then
   dbms_output.put_line(v_s ||' entspricht');   
 else
   dbms_output.put_line(v_s ||' entspricht NICHT!');
 end if;
END; -- Procedure