There are following business statements for an information system:①A customer submit 0 or more orders;②An order can only be submitted by one customer. There are two classes in the system “Customer” and “Order”. For each instance of Order Class, there are ____ instance(s) of Customer Class; while for each instance of Customer Class, there are ____ instance(s) of Order Class.
A: (1) 1 (2) 1
B: (1) 1 (2) 1 or more
C: (1) 1 (2) 0 or more
D: (1) 0 or more (2) 1
A: (1) 1 (2) 1
B: (1) 1 (2) 1 or more
C: (1) 1 (2) 0 or more
D: (1) 0 or more (2) 1
C
举一反三
- 中国大学MOOC: There are following business statements for an information system:①A customer submit 0 or more orders;②An order can only be submitted by one customer. There are two classes in the system “Customer” and “Order”. For each instance of Order Class, there are ____ instance(s) of Customer Class; while for each instance of Customer Class, there are ____ instance(s) of Order Class.
- Which of the following is the order of applying object-oriented concept in programming A: instance creating — class defining — use attributes or methods through the instance B: class defining — instance creating — use attributes or methods through the instance C: instance creating — use attributes or methods through the instance — class defining D: class defining — use attributes or methods through the instance —instance creating
- 哪种方式通过对比页面变化能判断 sql 注入（）。 A: order 1 和 order 2 B: ' or 1=1 和' or 1=2 C: '和'' D: ' and 1=1 和' and 1=2
- There are ______ many League members in Class 1 ______ in Class 2. A: more, than B: as, as C: so, as
- 设两个向量组α1,α2,...,αs和β1,β2,...,βs均线性相关,则() A: 有不全为0的数λ1,λ2,…,λs使λ1α1+λ2α2+…+λsαs=0和λ1β1+λ2β2+…λsβs=0 B: 有不全为0的数λ1,λ2,…,λs使λ1(α1+β1)+λ2(α2+β2)+…+λs(αs+βs)=0 C: 有不全为0的数λ1,λ2,…,λs使λ1(α1-β1)+λ2(α2-β2)+…+λs(αs-βs)=0 D: 有不全为0的数λ1,λ2,…,λs和不全为0的数μ1,μ2,…,μs使λ1α1+λ2α2+…+λsαs=0和μ1β1+μ2β2+…+μsβs=0
内容
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The number of subgroups of order 25 of an Abelian group of order 50 is ( ). A: 0 B: 1 C: 2 D: 3
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将矩阵[img=544x298]17da662f4927053.png[/img]写成MATLAB语言表达形式，下列正确的是（ ）。 A: A=[1 0 -1;1 0 1;1 2 1; 1 2 2] B: A=[1 -1 1 2;1 1 1 1;2 0 0 2] C: A=[1 1 1 1;2 0 0 2;1 -1 1 2] D: A=[1 2 1;1 0 -1;1 0 1;1 2 2]
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串S='aaab'，其next数组为（）? 0 2 0 0|0 1 2 0|-1 0 1 2|0 0 1 2
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电子2s1的运动状态可表示为（）。 A: n=2，l=0，m=0，s=+1/2 B: n=2，l=0，m=0，s=0 C: n=2，l=1，m=1，s=+1/2 D: n=2，l=0.m=-1，s=－1/2
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串S='aaab'，其next数组为（） A: -1 0 1 2 B: 0 0 1 2 C: 0 1 2 0 D: 0 2 0 0