问题 问答题 案例分析题

数据库安全与数据库备份

银行金融系统对数据库中的数据安全要求很高,必须在技术层面上采用必要的措施,以保证数据的有效和不丢失。数据库的备份与恢复是保证数据安全的一种基本方法,一般将数据库备份分为冷备份、热备份和数据导出,而数据导出根据导出数据的范围,又可以分为完全导出、增量导出和累计导出。

该金融系统上线初期,整个业务系统采用了内网方式运行,不与外网发生联系。为了保证数据库内部数据的安全,该银行信息中心的刘工提出的备份方案如表12-3所示。

信息中心的李工对刘工的方案提出了异议,认为数据库一旦发生故障,刘工的方案无法做到数据库的实时恢复,会导致业务数据的丢失,银行应该采用数据库冷备份和热备份相结合的方式来完成数据库的备份。

银行金融系统需要支持数据库的实时/秒级恢复(即恢复到故障之前的时间点上),请设计合理的备份策略,并说明其基本恢复过程。

答案

参考答案:

银行系统如果需要支持数据库的实时恢复或秒级恢复,需要采用冷备份和热备份相结合的方式来进行备份。基本的备份策略如表12-5所示。

冷备份与热备份的交替间隔时间可以根据自身特点来进行调整。

当数据库出现故障,需要恢复时,基本的步骤如下:

①恢复最近一次的冷备份数据。

②按照时间顺序,恢复热备份中备份的数据和日志文件。

③找到机器上未损坏的最后一个日志文件,将数据库恢复到该日志文件对应的时间点。

解析:

问题4是进行备份策略的选用,在做此策略时,需要注意冷备份与热备份相结合,这样既可以兼顾效率,又能让系统在出现故障后准确地恢复到故障前的状态,使损失降到最低。

阅读理解

Maybelle said she wouldn't be coming with me to the library. I asked why, and she said she could get all the short stories she wanted off the Internet. Saved walking all the way to the library, and putting up with my long chat on the way there, and on the way back. Maybelle is very direct like that, always has been.

"But, Maybelle, we've been walking to the library every' Monday for the last fifty years!"

She said," Why don't you get Internet'? We can send each other emails."

So I had to get Internet. I called the local high school. They said they'd send me a good student to tell me all about computers and such.

Evil thing, this Internet. Makes you lose old friends, forces you to learn new complex ideas, even if you're too old. But Maybelle said you have to be modern; otherwise, you're dead.

The kid came the next day. Tall skinny black kid, by tile name of Arsenius, said his work would cost me.

I said, "All right. As long as I get Internet."

"You need a computer, then you need to get hooked up," he said.

"Let's buy a computer and get hooked up, then."

"How much you want to spend?"

"Whatever it takes."

"How many rams you want?"

I wasn't going to show him my ignorance, so I said, "Whatever it takes."

"Let's go to the mall. You got a car?"

"In the garage."

When I opened the garage door, he gasped. Daddy's car is still there, a'57 Chevy. I never drive it. Walk everywhere.

I said," Let's walk. It's only a mile or so."

He said," Let's drive, or you will faint on me in this heat."

"Young man, I don't faint, never have. We're walking."

"I get paid by the hour," he said. "Walking will cost you a lot more. Also, you feel like carrying a computer a mile or so?"

小题1:What kind of person is Maybelle?

A.She always says what she means in an honest way.

B.She no longer likes reading in her old age.

C.She doesn't want to be friends with the writer any mort.

D.She doesn't want to keep up with the time.小题2:Why does the writer want to have Internet at his place?

A.Because the writer believes that one is never too old to learn.

B.Because the writer thinks that it is better late than never.

C.Because of the pressure from people of his age.

D.Because of the convenience the Internet will bring.小题3:Arsenius gives _________ reasons for driving to the mall.

A.two

B.three

C.four

D.five

问答题 简答题