DECLARE
  CURSOR emp_cursor IS SELECT employeename,sal FROM employee 
  FOR UPDATE OF sal;--在sal列上加共享鎖
  v_ename employee.employeename%TYPE;
  v_oldsal employee.sal%TYPE;
BEGIN
  OPEN emp_cursor;
  LOOP
    FETCH emp_cursor INTO v_ename,v_oldsal;
    EXIT  WHEN emp_cursor%NOTFOUND;
    IF v_oldsal<2500 THEN
      UPDATE employee SET sal=sal+150 WHERE CURRENT OF emp_cursor;
    END IF; 
    END LOOP;
  CLOSE emp_cursor;
END;