数据库管理系统通常提供授权功能来控制不同用户访问数据的权限,这主要是为了实现数据库的

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问题:

数据库管理系统通常提供授权功能来控制不同用户访问数据的权限,这主要是为了实现数据库的( )。

A.可靠性

B.一致性

C.完整性

D.安全性

考点:计算机等级考试数据库技术计算机三级(数据库技术)12
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苹果酸常用做汽水、糖果的添加剂。写出苹果酸分别与下列物质反应的化学方程式:

(1)Na __________________________。

(2)Na2CO3___________________________。

(3)CH3CH2OH(H2SO4,△)___________________________。

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国家信息化的首要核心任务是()。

A.信息技术应用

B.信息资源的开发利用

C.建设国家信息网络

D.发展信息技术与产业

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金融法的基本原则是什么?

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Passage Two

If there is one thing I’m sure about, it is that in a hundred years from now we will still be reading newspapers. It is not that newspapers are a necessity. Even now some people get most of their news from television or radio. Many buy a paper only on Saturday or Sunday. But for most people reading a newspaper has become a habit passed down from generation to generation.

The nature of what is news may change. What basically makes news is what affects our lives—the big political stories, the coverage of the wars, earthquakes and other disasters, will continue much the same. I think there will be more coverage of scientific research, though. It’s already happening in areas that may directly affect our lives, like genetic engineering. In the future, I think there will be more coverage of scientific explanations of why we feel as we do—as we develop a better understanding of how the brain operates and what our feelings really are.

It’s quite possible that in the next century newspapers will be transmitted electronically from Fleet Street and printed out in our own home. In fact, I’m pretty sure that how it will happen in the future. You will probably be able to choose from a menu, making up your own newspaper by picking out the things you want to read--sports and international news, etc.

I think people have got it wrong when they talk about competition between the different media. They actually feed off each other. Some people once foresaw that television would kill off newspapers, but that hasn’t happened. What is read on the printed page lasts longer than pictures on a screen or sound lost in the air. And as for the Internet, it’s never really pleasant to read something just on a screen.

The phrase“feed off”in the last paragraph means()·

A.depend on

B.compete with

C.fight with

D.kill off

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赫克歇尔-俄林的要素禀赋说

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