问题 单项选择题

确定系统边界应在数据库设计的 (32) 阶段进行;关系规范化是在数据库设计的 (33) 阶段进行。

A.需求分析

B.概念设计

C.逻辑设计

D.物理设计

答案

参考答案:C

解析:

[分析]: 需求分析阶段的任务是:对现实世界要处理的对象(组织、部门、企业等)进行详细调查,在了解现行系统的概况,确定新系统功能的过程中,确定系统边界、收集支持系统目标的基础数据及其处理方法。
逻辑设计阶段的任务之一是对关系模式进一步地规范化处理。因为生成的初始关系模式并不能完全符合要求,还会有数据冗余、更新异常存在,这就需要根据规范化理论对关系模式分解之后,消除冗余和更新异常。要注意的是,有时根据处理要求,可能还需要增加部分冗余以满足处理要求。逻辑设计阶段的任务就需要作部分关系模式的处理,分解、合并或增加冗余属性,提高存储效率和处理效率。

阅读理解

阅读理解。

      Mrs. Brown was very fat. Her husband thought she should have a balanced diet, and he made her

not eat meat or cakes.

      One morning, Mrs. Brown made a nice cake for her husband, and he ate half of it. After he went

out, Mrs. Brown cut a very small piece of cake and ate it. It was very delicious. Then she cut another

piece and ate it, too. In a few minutes she ate up the cake. "My husband is going to be very angry."

She thought, "What should I do?" She made another cake very quickly, ate half of it, and put the other

half on the table. Mr. Brown came back later and when he saw the half of the cake on the table, he was

very happy.

1. How many cakes did Mr. Brown eat that morning?

A. One cake.

B. One and a half cakes.

C. Half of the cake.

D. Two cakes.

2. Which of the following is true?

A. Mrs. Brown ate half of the first cake and left the other half for her husband.

B. Mrs. Brown ate half of the first cake and half of the second one that morning.

C. Mr. Brown ate two cakes that morning.

D. Mrs. Brown didn't eat any cakes that morning.

3. Mrs. Brown made another cake because ____.

A. her husband liked eating cakes

B. her husband didn't like the first cake

C. she wanted to eat more cakes

D. she didn't want her husband to be angry

4.  Why was Mr. Brown's husband very happy in the end?

A. Because he was very hungry.  

B. Because Mrs. Brown made it for him. 

C. Because he thought Mrs. Brown ate no cakes. 

D. Because the cake was more delicious than the first one. 

5. Why couldn't Mrs. Brown eat meat or cakes?

A. Because meat and cakes are not delicious.

B. Because Mr. Brown liked eating them.

C. Because meat and cakes could make her fatter.

D. Because meat and cakes will make her sick.

单项选择题