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关于数据库系统中的日志文件，有下列说法：
Ⅰ．事务故障恢复和系统故障恢复时都必须使用日志文件
Ⅱ．在动态转储过程中，对数据库所做的修改都被记录在日志文件中
Ⅲ．数据库管理系统进行数据修改操作时，一般是先写数据库，然后再写日志文件
Ⅳ．建立检查点的主要目的是通过减小日志文件的总体数据规模，从而提高数据恢复效率
Ⅴ．日志文件有利于用户对数据库系统的违规操作开展核查审计工作
以上说法正确的是______。
A)仅Ⅰ、Ⅱ和Ⅴ
B)仅Ⅰ和Ⅱ
C)仅Ⅰ、Ⅲ和Ⅴ
D)仅Ⅱ、Ⅲ、Ⅳ和Ⅴ
A.
B.
C.
D.

A.事务故障恢复和系统故障恢复时都必须使用日志文件
B.在动态转储过程中，对数据库所做的修改都被记录在日志文件中
C.数据库管理系统进行数据修改操作时，一般是先写数据库，然后再写日志文件
D.建立检查点的主要目的是通过减小日志文件的总体数据规模，从而提高数据恢复效率
E.日志文件有利于用户对数据库系统的违规操作开展核查审计工作

【参考答案】

A
解析：日志文件的具体作用为：①事务故障恢复和系统故障恢复必须使用日志文件；②在动态转储方式中必须建立日志文件......

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