问题 填空题

在数据库设计的四个阶段中,每个阶段都有自己的设计内容。“为哪些表、在哪些字段上、建什么样的索引。”这一设计内容应该属于______设计阶段。

答案

参考答案:物理

解析: 数据库设计的四个阶段是:需求分析、概念设计、逻辑设计和物理设计。其中物理设计阶段的主要任务是:对数据库中数据在物理设备上的存放结构和存取方法进行设计。“为哪些表、在哪些字段上、建什么样的索引”便是为数据库设计索引存放的方法。
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,在了解新系统的概况、确定新系统功能的过程中,收集支持系统目标的基础数据及其处理方法。
概念设计的任务是产生反映企业组织信息需求的数据库概念结构,即概念模型。
逻辑设计的目的,是从概念模型导出特定的DBMS可以处理的数据库的逻辑结构(数据库的模式和外模式),这些模式在功能、性能、完整性、一致性约束及数据库可扩充性等方面都满足用户的要求。

阅读理解

阅读理解。

       Hunter and Nina are husband and wife. They get up at about 4:50 in the morning. When many people are

still sleeping in their warm beds, they are working, they work outside and clean something. They don't work

when it is raining, they also work on weekends.

       Her name is Sara. She sometimes goes to work in the morning, and sometimes goes to work at night when

she is on duty. She works in a big building. There are many beds in it. She wears a white hat and a white dress.

She says. "I help doctors. I meet many people every day. I look after them. They need my help. That's my job.

It's hard, but I like it." 

       He is Jim's father. He usually leaves home very early. He doesn't work in a factory. He goes to work on

foot or by bike. It is far from his home. He usually works in the day and has his lunch outside in the sun. His

work is very hard. He often brings us rice, eggs and vegetables. He can have a good rest in winter.

       Her name is Ann. She goes to work by bus every day. She works in a building. It opens at 8 a. m and

closes at 6 p.m. There is a lot of good food, drinks and other things where she works. Children like to go there.

She meets a lot of people every day. She often says, "Can I help you?" when she meets people. She says, "My

work is not easy, I must stand all day and be friendly to everyone."

根据上面四段文字,依据逻辑推理出下列答案。

1. What jobs do they have? Hunter and Nina are             .

2. —When don't Hunter and Nina work?   —They don't work when ______.

3. —Does Sara like her job?   —______.

4. —Which season does Jim's father stop working?  — ______.

5. —What does Ann often say when she meets people?   — ______.

填空题