一范式的表格已经满足了关系的基本约束条件,可以描述为一个关系,但是这种关系存在的问题

题型:单项选择题

问题:

一范式的表格已经满足了关系的基本约束条件,可以描述为一个关系,但是这种关系存在的问题会比较多。归纳起来主要有三类,其中不包括()。

A.插入异常

B.删除、修改异常

C.数据冗余大

D.数据关系过于复杂

考点:注册会计师管理信息系统的应用与管理管理信息系统的应用与管理题库
题型:单项选择题

矩形具有而平行四边形不一定具有的性质是[ ]

A.对边相等

B.对角线互相平分

C.对角线互相垂直

D.对角线相等

题型:单项选择题

在某一温度下,两个电路元件甲和乙中的电流与电压的关系如图

1所示,由图可知,元件甲的电阻是   Ω,将元件甲、乙并联

后接在电压为2V的电源两端,则流过元件甲的电流是   A,

流过元件乙的电流是   A。

题型:单项选择题

一块木块能浮在水面上,也能浮在酒精面上.下列说法中正确的是(  )

A.它在两种液体中受到的浮力相等,但在酒精中浸人的体积大些

B.它在两种液体中受到的浮力相等,并且排开液体的体积也相等

C.由于酒精的密度较小,所以它浸在酒精中时受到的浮力小些

D.它在两种液体中受到的浮力不等,排开液体的体积也不相等

题型:单项选择题

Waseem, aged 15, was very excited because he was to start summer camp at his school. However, his father was taking the family’s only car to Islamabad on business for a month. Waseem had been saving his pocket money for some time so he decided to buy a bicycle. The bicycle he liked was priced at Rs. 7,000·00, however Waseem had only Rs. 2000·00 with him. The shopkeeper knew Waseem and his father, so he allowed Waseem to take the bicycle on the promise to pay the remaining Rs. 5,000·00 on his father’s return. Waseem rode the bicycle to and from the summer camp for 15 days after which it was damaged in a fall.Waseem’s father has returned from the business trip and wants to return the bicycle. The shopkeeper has refused and wants the payment of the remaining Rs. 5,000·00.Required:Under the Contract Act, 1872, advise Waseem’s father on the status of the contract between Waseem and the shopkeeper, and any obligations that Waseem or Waseem’s father may owe to the shopkeeper. (10 marks)

题型:单项选择题

在油断路器中是使用什么方法来灭弧的?

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