【摘要】 封锁与可串行化调度是数据库并发操作采取的两种主要措施。判断一个调度是否可串行化调度的最有效方法是两段锁协议。但是，一方面，事务遵守两段锁协议只是可串行化调度的充分条件而不是必要条件；另一方面，遵守两段锁协议的事务仍可能发生死锁。文中给出了一种算法，利用该算法，不仅可判断出一个调度是否为可串行化调度，而且可判断出该调度是否会发生死锁。更多还原

【Abstract】 Locking and serializable schedule, are two main measures for concurrent operation of database. The most effective method for deciding if a schedule is serializable is Two-phase locking protocol. However,on the one hand,The Two-phase locking protocol is only sufficient condition but necessary condition of serializable schedule;on the other hand,the transactions keeping Two-phase locking protocol possibly occur deadlock. This paper gives an algorithm. With the algorithm,we can not only decide if a schedule is serializable but also decide if a schedule occurs deadlock.更多还原