问题
单项选择题
There is an hour to go. Could we sit somewhere to have a drink?()
A.Have a try.
B.Sure.
C.Don‘t go, please.
D.No, thanks.
答案
参考答案:B
There is an hour to go. Could we sit somewhere to have a drink?()
A.Have a try.
B.Sure.
C.Don‘t go, please.
D.No, thanks.
参考答案:B
设有两个事务T1和T2,其并发操作序列如下表所示。下列说法中正确的是
步骤 | T1 | T2 |
1 | 读A=100 | |
2 | A=A*2写图 | |
3 | 读A=200 | |
4 | ROLLBACK |
A.该操作序列不存在问题
B.该操作序列丢失修改
C.该操作序列不能重复读
D.该操作序列读出"脏"数据