第27题: [单项选择]A survey of 100 persons revealed that 72 of them had eaten at restaurant P and that 52 of them had eaten at restaurant Q. Which of the following could not be the number of persons in the surveyed group who had eaten at both P and Q A. 20 B. 24 C. 30 D. 50 E. (E) 52 参考答案:A
第29题: [单项选择]80x86宏汇编语言中的变量有三个属性,下列不是其属性的选项是( )。 A. 段属性 B. 偏移地址属性 C. 类型属性 D. 范围属性 参考答案:D 答案解析:第三范式:如果关系模式R是第二范式,且没有一个非码属性传递函数依赖于候选码。而此题的R有“某个非码属性传递函数依赖于码”,所以可知它必定不属于3NF,至多属于2NF。