Since pessimistic session locks can be removed as described above, the application that obtained the lock should always check to see if it is still in force before updating data.
如上所述，由于可以删除悲观会话锁，因此获得锁的应用程序始终需要在更新数据之前检测锁是否有效。
2
Libraries are expanding services that let patrons virtually 'check out' an e-book through the Internet, with e-book files that automatically lock down after the end of the loan period.
图书馆也扩展了服务，读者可以通过网络借阅电子书。借阅期到了之后，图书会自动锁定，无法阅读。
3
Most of these instructions are in place to check for the initialization of I, and to perform a thread-safe initialization using a lock.