BEGIN TRAN tran_upd_courses
   update courses
   set hour=60
   where cid='10051     '
   BEGIN TRAN tran_upd_teachers
       insert into teachers
       values('1234567890','zs','my@zsu.edu.cn',3000)
   IF @@ERROR!=0 
      BEGIN
       -------撤消事務
      ROLLBACK TRAN tran_upd_teacher
      PRINT '更新教師表失敗'
      RETURN
      END
   --提交內層事務
   COMMIT TRAN tran_upd_teachers
   ----提交外層事務
   COMMIT TRAN tran_upd_courses