问题
单项选择题
关系表中的每一横行称为一个______。
A) 元组
B) 字段
C) 属性
D) 码
答案
参考答案：A
解析： 在关系数据库中，关系模型采用二维表来表示，简称“表”。二维表是由表框架及表元组组成。在表框架中，按行可以存放数据，每行数据称为元组。
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关系表中的每一横行称为一个______。
A) 元组
B) 字段
C) 属性
D) 码
参考答案：A
解析： 在关系数据库中，关系模型采用二维表来表示，简称“表”。二维表是由表框架及表元组组成。在表框架中，按行可以存放数据，每行数据称为元组。
On Sunday morning, I usually get up very late. I wash my face, and then go out to do morning exercises. It is about 8: 40 am. After I eat my , I often go to a shopping centre my mother. The shopping centre is our home, so we walk there. It takes us about 20 minutes to get there. The shopping centre has a good . It is called“蓝莓购物中心”in Chinese. It doesn’t have an English name. Can you it in English? It is new and big. There are many things there, such as TVs, fridges, computers, clothes, food drinks. There are many every day. There are men and women, the old and the . do many people come here to buy things? Do you know? Let me tell you. The workers there are always nice and friendly. The things there are usually good but not . If you come to my home, I can take you there and have a look.
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