事务T1符合两段锁封锁法的序列是（）
A: LOCK S(A)...LOCKS S(B) ...UNLOCK (B) ... UNLOCK (A)
B: LOCK S(A) UNLOCK (A) LOCK S(B) UNLOCK (A)
C: LOCK S(B) LOCK X(A) UNLOCK (A) LOCK S(C)
D: UNLOCK (A) UNLOCK (B) LOCK X(A) LOCK X(B)
A: LOCK S(A)...LOCKS S(B) ...UNLOCK (B) ... UNLOCK (A)
B: LOCK S(A) UNLOCK (A) LOCK S(B) UNLOCK (A)
C: LOCK S(B) LOCK X(A) UNLOCK (A) LOCK S(C)
D: UNLOCK (A) UNLOCK (B) LOCK X(A) LOCK X(B)
举一反三
- 下面()是使用Application对象时防止竞争的代码?Application. ; //锁定Application对象Application[“counter”]=(int) Application[“counter”]+1;Application. ; //解除对Application对象的锁定 A: lock unlock B: Lock UnLock C: Lock() UnLock() D: UnLock() Lock()
- 关于Application对象的方法，下面说法正确的是（） A: 只有Lock方法 B: 只有Unlock方法 C: 没有Lock方法和Unlock方法 D: 有Lock方法和Unlock方法
- 已知事务T1的封锁序列为：LOCK S(A)…LOCK S(B)…LOCK X(...B)则遵守两段封锁协议的事务是（
- My mother was in a hurry and forgot to lock the door. She left the door _________. A: lock B: locked C: unlock D: unlocked
- He asked whether he was to lock the car or leave it (unlock) ______.