1Z0-053 争议题目解析498

1Z0-053 争议题目解析498

考试科目：1Z0-053
题库版本：V13.02

题库中原题为：

498.The database Is configured in ARCHIVELOG mode. The database needs to be up 24 X 7. You want
to perform user managed backup for the data files of the HR_DATA tablespace. To accomplish the task,
you issued the following command:
SQL>ALTER TABLESPACE hi_data BEGIN BACKUP;
Which two statements are true in this scenario? (Choose two.)
A. No transaction on the tablespace is allowed but you can perform queries.
B. The tablespace will automatically come out of backup mode when the file copy is complete.
C. The checkpoint change number is frozen in headers of the data files until the file is removed from
backup mode.
D. The database writes the before image of an entire block to the redo stream before modifying. block tor
the first time.
Answer: AC

争议点：
网上有人说应该选择CD，我个人认为也认为应该是CD。
而且题库答案A选项明显错误。
处于备份模式的表空间，是可以进行新事物的，只是记录在redo日志中。

戴总整理的题库，该题也是CD选项。

此外，Riveore的解析更明白：
http://blog.csdn.net/rlhua/article/details/19545301

初步结论：
选择CD。