设有员工实体Emp(员工号，姓名，性别，年龄，出生年月，联系方式，部门号)，其中“联系方式”要求记录该员工的手机号码和办公室电话，部门号要求参照另一部门实体Dept的主码“部门号”。Emp实体中存在派生属性和多值属性： (54) ；对属性部门号应该进行 (55) 约束；可以通过命令 (56) 修改表中的数据。
（54）处填（）。
A．年龄和出生年月
B．年龄和联系方式
C．出生年月和联系方式
D．出生年月和年龄
参考答案：B
| 完形填空。 | ||||
| One day, a young man asked Albert Einstein, 1 great German scientist, 2 the secret (秘密) of success (成功) was.The scientist 3 him that the secret of success is hard work. A few days 4 the young man asked him the 5 question again. Einstein was very 6 . He did not say 7 , but wrote a few 8 on a piece of paper and 9 it to the young man. The young man looked 10 the piece of paper. On it was 11 : A=X+Y+Z." What 13 this mean?" asked the young man."A means success," 14 the old scientist."X means hard work, Y means good methods (方法), and Z…Z mean 59 talking and start to 15 ." | ||||
|