CREATE OR REPLACE FUNCTION PLPDF_SESSION_IS_VALID(
  p_session_id NUMBER
  ) RETURN BOOLEAN IS
  l_ret BOOLEAN;
  l_id NUMBER;
BEGIN
  BEGIN
    SELECT id INTO l_id
    FROM FLOWS_020000.WWV_FLOW_SESSIONS$
    WHERE id = p_session_id;
    l_ret := TRUE;
  EXCEPTION
    WHEN NO_DATA_FOUND THEN
      l_ret := FALSE;
  END;
  RETURN l_ret;
END;
/