问题 单项选择题

某高校的教学管理系统采用如下形式:学生、教师的相关信息以及学生选课情况、教师授课情况、学生成绩均存储在学校教务处主机中,学生通过浏览器进行选课、退课、选课查询以及成绩查询。支持多名学生同时访问。数据库的这种方式属于()。

A.集中式数据库体系结构

B.C/S数据库体系结构

C.Web数据库体系结构

D.并行数据库体系结构

答案

参考答案:C

解析:

数据库应用体系结构分为:集中式数据库系统、C/S数据库体系结构、Web数据库、并行数据库系统、分布式数据库系统。 · 集中式数据库系统中,数据是集中的,数据的管理也是集中的,数据库系统的所有功能,从形式的用户接口到DBMS核心都集中在DBMS所在的计算机上。 · C/S数据库体系结构中,客户机与服务器CPU之间职责明确,客户机主要负责数据表示服务,而服务器主要负责数据库服务。ODBC和JDBC标准定义了应用程序和数据库服务器通信的方法,也即定义了应用程序接口,应用程序用它来打开与数据库的连接、发送查询和更新以及获取返回结果等。 · Web数据库系统中,用户利用浏览器作为输入接口输入所需要的数据,浏览器将这些数据传送给网站,而网站再对这些数据进行处理,最后网站将操作结果传回给浏览器,通过浏览器将结果告知用户。 · 并行体系结构的数据库系统是多个物理上连在一起的CPU,而分布式系统是多个地理上分开的CPU。 · 分布式DBMS包括物理上分布、逻辑上集中的分布式结构和物理上分布、逻辑上分布的分布式数据库结构两种。故选C。

阅读理解

   Many scientists are now exploring the idea of going to live on Mars. Some other scientists from the MASA AMES Center(美国宇航局) have already started the creation of a “Mars town” and many others are in fact already experimenting with it. Of course, these experiments are done on Earth itself but this “Mars town” has an environment practically like that of Mars.

The astronauts working in these towns wear their space suit and also do everything they would really have to carry out if they ever go to Mars in the future.

But Mars would be like Earth, a temporary(临时的) place for humans. When the Sun starts swallowing up(吞掉) the planets, Mars will disappear only hours after Earth. So Mars only seems to be the ideal place to spread the human beings. It is also a good location to send humans if ever there is a disaster on Earth. By saying disaster, I mean asteroids(小行星) hitting and things like that.

If we humans do not want to disappear when Earth or Mars gets swallowed up, we will have to go and live beyond the solar system. But are there any planets outside our solar system prepared to support life? Astronomers’ answer is:

“If Earth can support life, why can’t other planets do the same too? Astronomers have already discovered a Jupiter(木星)- like planet orbiting a Sun-like star, so why not an Earth-like planet orbiting a Sun-like star?

To achieve this goal though, many other problems have to be taken into consideration. How do we transform(改造) a dusty planet like Mars into one more or less like our Earth? How should we go on? There is still a long way to go.

小题1: The “Mars town” mentioned in the passage is ___________

A.a research base on Mars.

B.an experimental lab built on Earth.

C.a strange place on Mars .

D.a town existing in scientists’ imagination小题2: We can know from the passage that astronomers probably think ____________

A.it is impossible to transport humans to other planets.

B.there may be an Earth-like planet outside the solar system

C.humans will move to the new-found Jupiter-like planet

D.there’s no need for humans to move beyond the solar system.小题3:Why would Mars only be a temporary(临时) place for humans?

A.The conditions there would be too hard for the human beings

B.There would be more disasters like asteroids hitting.

C.It would disappear when Earth disappeared.

D.It would be too hot to live on.小题4:The underlined word “orbiting” in the fifth paragraph is closest in meaning to “________”

A.moving around

B.getting close to

C.passing by quickly

D.going through小题5:Which of the following would be the best title for this passage?

A.Mars Town

B.Living on Mars

C.The Future of Earth

D.Where to live in the Future

单项选择题