【填空题】
4.根据不同的数据模型，数据库管理系统可分为___、___、___和面向对象型
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层次模型|网状模型|关系模型
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相关试题
【单选题】
一个关系中的各个元组___
A. 前后顺序不能任意颠倒，一定要按照输入的顺序排列
B. 前后顺序可以颠倒，不影响库中的数据关系
C. 前后顺序可以任意颠倒，到排列顺序不同，统计处理的结果就可能不同
D. ”前后顺序不能任意颠倒，一定要按照关键字段值的顺序排列
【单选题】
有一个关系：学生（学号，姓名，系别）规定学号的值域是8个数字组成的字符串，这一规则属于()
A. 实体完整性约束
B. 参照完整性约束
C. 用户自定义完整性约束
D. 关键字完整性约束
【单选题】
已知关系1：厂商(厂商号，厂名)，关系1的主码的为厂商号；关系2:产品(产品号，颜色，厂商号)，关系2的主码为产品号，外码为厂商号。
假设两个关系中已经存在如表2-14和表2-15所示的元组，若再往产品关系中插入如下元组：I（P03,红,C02），II(P01,蓝，C01), I I I(P04,白C04),IV(P05， 黑，null)
表2-14厂商
厂商号 厂名
C01 宏达
C02 立仁
表2-15产品
产品号 颜色 厂商号
P01 红 C01
P02 黄 C03
能够插入的元组是（）
A. I,I I,I I I
B. I,I I
C. I,II
D. I,IV
【单选题】
在关系S (NAME, SNO, DEPART)中规定DEPART属性只能是计算机。这规定属于___
A. 用户自定义完整性
B. 参照完整性
C. 实体完整性
D. 固定完整性
【单选题】
在下面的两个关系中，职工号和部门号分别为职工关系和部门关系的主码。职工(职工号，职工名，部门号，职务，工资)郁门(部门号，部门名，部门人数:工资总额)在这两个关系的属性中，只有一个属性是外码，它是___
A. 职工关系的职工号
B. 职工关系的部门号
C. 部门关系的部门号
D. 部门关系的部门名
【填空题】
3.已知“系【系编号，系名称，系主任，电话，地点】”和“学生【学号，姓名，性别，入学日期，专业，系编号】”两个关系，“系”关系的主关键字是___，“学生”关系的主关键字是___，外关键字是___
【单选题】
有关系模式“学生【学号，课程号，名次】”，若每一名学生每门课程有一定的名次，每门课程每一名次只有一名学生， 则以下叙述中错误的是___。
A. (学号，课程号)和(课程号，名次)都可以作为候选码
B. 只有(学号，课程号)能作为候选码
C. 关系模式属于第3范式
D. 关系模式属于BCNF
【单选题】
4.关系数据库规范化理论是为解决关系数据库中的___问题而引入的。
A. 插入、更新、删除和数据冗余
B. ，提高查询速度
C. 减少数据操作的复杂性
D. 保证数据的安全性和完整性
【单选题】
若关系模式R 【A, B】已属于3NF，下列说法中___是正确的。
A. 它一定消除了插入和删除异常
B. 可能存在一定的插入和删除异常
C. 一定属于BCNF
D. A和C都是
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Tom is a book lover. ______ likes reading very much.
A. He B. She C. You D. It
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—May I listen to the music here, Mr. White?
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【单选题】
6. A friend of my ____ and I are going to visit_______ next week．
A. father; Browns B. father's; Browns
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7. She ______ very hard since she came to our school.
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8. — Who will send you to the new school, your mom or your dad?
— _______. Ill go there by myself.
A. Both B. Either C. Neither D. None
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9.—Well do what we can ____English well this term．
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A. study B．to study C. be studied D. be studying
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10. —I’m going to Flower Bookstore. Could you tell me ______?
— Sorry, I don’t know. I’m new here.
A. where it is B. where was it C. where is it D. where it was
A. A
B. B
C. C
D. D
【单选题】
11. How do you like the dishes, Eric?
— Fantastic! Nothing tastes ________.
A. nice B. better C. terrible D. worse
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B. B
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【单选题】
12. ______ Lin Feng has to work late, she always wears a smile on her face.
A. Because B. If C. Until D. Though
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【单选题】
13.You can save money _______ you buy cheaper things.
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14. We will have a _________ holiday after the exam．
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B. B
C. C
D. D
【单选题】
15. —We will build an underground in Xuzhou before 2015．
— Wow, _______! Will it pass our place?
A. what an excited news B. how excited the news is
C. what exciting news D. how exciting
A. A
B. B
C. C
D. D
【单选题】
16. — Emily, here’s a dictionary．I hope it will help you in some way．
— Thank you．It’s ________ what I need．
A. almost B. still C. only D. just
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B. B
C. C
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【单选题】
17. —Oh．I’m hungry．Mum, can I have the hamburger on the plate?
—No．It tastes ．
A. terribly B. terrible C. good D. well
A. A
B. B
C. C
D. D
【单选题】
18. —We can invite our teachers to the farewell party next Saturday.
—Yes, ______? I’ll call them at once.
A. what for B. what C. why not D. why
A. A
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C. C
D. D
【单选题】
19.You can ________ ask the old man to move away to any other place because he has lived ________ here for at least sixty years．
A. hardly; alone B. hard; alone
C. hardly; lonely D. hardly; lonely
A. A
B. B
C. C
D. D
【单选题】
20.—I’m going back to see my grandparents this weekend．
—________．
A. It’s very nice of you B. You’d better hurry
C. Say goodbye to them D. Give my best wishes to them
A. A
B. B
C. C
D. D
【单选题】
21.—Why not take ____ umbrella with the sign “Made in China”? It is useful.
—What _______ good advice it is!
A. an; a B. a; a C. an; \ D. \; a
A. A
B. B
C. C
D. D
【单选题】
22. —Do you know the boy________ is sitting next to Peter?
— Yes. He is Peter’s friend. They are celebrating his ________ birthday.
A. who; ninth B. that; ninth C. /; ninth D. which; ninth
A. A
B. B
C. C
D. D
【单选题】
23. It was dark, ______ I couldnt see what was happening.
A. or B. though C. but D. so
A. A
B. B
C. C
D. D
【单选题】
24.—You can use MSN to talk with Vivien on the Internet.
—I know. But can you tell me ________?
A. what I can use it B. when I can use it
C. why can I use it D. how can I use it
A. A
B. B
C. C
D. D
【单选题】
25. _______ are you going to the School Uniform Exhibition, Amy ?
To learn about different styles of school uniform.
A. What B. Where C. Which D. Why
A. A
B. B
C. C
D. D
【单选题】
( ) 26. Where does the writer of "The little Prince" come from?
A．England． B．France． C．America． D．China．
A. A
B. B
C. C
D. D
【单选题】
( ) 27. What does the prince do after the fox tells him a secret?
A．He cares more about a flower and a sheep．
B．He meets many more strange adults on other planets．
C．He realizes his love for the rose and he goes back to his planet．
D．He discovers interesting things such as a snake, other roses and a fox
A. A
B. B
C. C
D. D
【单选题】
( ) 28. What does "The little Prince" mainly talk about? It' s about _________．
A．the adult world B．the planet B -612
C．a rose and a fox D．the adventure of a young prince
A. A
B. B
C. C
D. D
【单选题】
( ) 29. What is the writer's main purpose（目的）in writing this passage？
A．To tell the readers his life story．
B．To tell people what kind of person his father was．
C．To tell the readers what present he got from his father．
D． To let people know how poor he was．
A. A
B. B
C. C
D. D
【单选题】
( ) 30. Why did the father not ask his son not to do this and do that？
A．Because he felt quite confident of his son．
B．Because he was born from a poor family．
C．Because he was a man of few words．
D．Because he didn't want to be much too strict with his son．
A. A
B. B
C. C
D. D
【单选题】
( ) 31. What would someone learn from this passage？
A．How to live by oneself． B．How to stand on one's own feet．
C．What a good father should do． D．What the self-important is like．
A. A
B. B
C. C
D. D
【单选题】
( ) 32. What may be the proper Chinese for the underlined part in the passage？
A．闲暇时光 B．学费 C．精神空虚 D．经济不足
A. A
B. B
C. C
D. D
【单选题】
( ) 33. Why did Natalie Smith pay for the six cars behind her?
A. She had seven tickets.
B. She hoped to please others.
C. She knew the car drivers well.
D. She wanted to show kindness.
A. A
B. B
C. C
D. D
【单选题】
( ) 34. Judy Foreman copied down the phrase because she ___ .
A. thought it was beautifully written
B. wanted to know what it really meant
C. decided to write it on a warehouse wall
D. wanted her husband to put it up in the classroom
A. A
B. B
C. C
D. D
【单选题】
( ) 35. Who came up with the phrase according to the passage?
A. Judy Foreman. B. Natalie Smith. C. Anne Herbert D. Alice Johnson.
A. A
B. B
C. C
D. S
【单选题】
( ) 36. What can we infer from the last paragraph?
A. People should practice random kindness to those in need.
B. People who receive kindness are likely to offer it to others.
C. People should practice random kindness to strangers they meet.
D. People who receive kindness are likely to pay it back to the giver.
A. A
B. B
C. C
D. D
【单选题】
( ) 37.The greatest river for navigation is ___________.
A. the Nile B. the Amazon C. the Mekong D. the Mississippi
A. A
B. B
C. C
D. D
【单选题】
( ) 38. From a dam, people can use the water for ___________.
A. keeping the rivers clean B. only making electricity
C. irrigation and making electricity D. washing clothes
A. A
B. B
C. C
D. D
【单选题】
( ) 39. The water in the river is polluted because of _____________.
A. people's drinking water too much B. people's swimming in the river too much
C. chemicals and other materials D. people's building a dam across a river
A. A
B. B
C. C
D. D
【单选题】
( ) 40. The best title of the passage is ___________.
A. Rivers in Cities B. The importance of Rivers
C. Transportation D. Natural Resources
A. A
B. B
C. C
D. D
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