通過Oracle函式返回一個UUID

create or replace function F_GET_UUID(p_length in INT) return varchar2 is
  Result varchar2(200);
/*************************************************************
*說明：返回一個指定長度不超過33位的UUID字串
*
**************************************************************/
  V_LENGTH VARCHAR2(33) := P_LENGTH;
  V_UUID   VARCHAR2(33) ;
begin
  select sys_guid() into V_UUID from dual;
  IF V_LENGTH IS NULL OR V_LENGTH = '' THEN
    V_LENGTH := 30;
  END IF;
  IF V_LENGTH > 33 OR V_LENGTH <=0 THEN
    V_LENGTH :=30;
  END IF;

  Result := substr(V_UUID,0,V_LENGTH);

  --dbms_output.put_line(Result);
  return(Result);
end F_GET_UUID;