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【简答题】
假定一个图书馆借阅管理系统包含 3 个实体: 一是“图书”实体集,属性有书号、品种、数量与存放位置;二是“借阅人”实体集,属性有借书证号、姓名、借书人单位;三是“出版社”实体集,属性有出版社编号,出版社名、电话、邮编、地址。 借阅人和图书存在借阅联系,借阅需要登记借书日期和还书日期。任何人可借多种书,任何一种书可为多个人所借;当需要时,可通过数据库中保存的出版社的等信息下应出版社增购有关书籍。一个出版社可出版多种书籍,同一本书仅为一个出版社版。 根据以上情况和假设,试作如下设计: ( 1 )构造满足需求的 E-R 图。 ( 2 )转换为等价的关系模式结构。
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反馈参考答案：
举一反三
【单选题】For some real number A, the graph of the line y=(A+1)x+8 in the standard (x,y) coordinate plane passes through (2,6). What is the slope of this line?
A.
-4
B.
-3
C.
-1
D.
3
E.
7
【判断题】Forced-draft cooling towers force air inmechanically by the use of fans on the top side of the tower.
A.
正确
B.
错误
【单选题】A large number of students in our school ____ from the countryside; the number _____ growing these years.
A.
is; has been
B.
are; has been
C.
is; have been
D.
are; have been
【单选题】def chanageInt(number2): number2 = number2+1 print("changeInt: number2= ",number2) #调用 number1 = 2 chanageInt(number1) print("number:",number1) 打印结果哪项是正确的
A.
changeInt: number2= 3 number: 3
B.
changeInt: number2= 3 number: 2
C.
number: 2 changeInt: number2= 2
D.
number: 2 changeInt: number2= 3
【简答题】Forced-draft cooling towers force air inmechanically by the use of _______ on the lower side of the tower.
【简答题】An_______ tower is anotherkind of cooling tower that produces airflow mechanically (Figure 8.6). Itdiffers from the forced-draft cooling tower in that it pulls air ______ the tower rather than forcing...
【简答题】number = (number)
x = y = z = (x)
(y)
(z)
a, b = , (a)
(b)A. 2 1 1 1 1 2 B. 1 1 1 1 1 2 C. 1 2 1 1 1 2 D. 1 1 1 1 2 2
【单选题】The number “ 1 “ in room number or telephone number is read as
A.
y ā o
B.
yào
C.
yóu
D.
y ī
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