题目内容
设有员工实体 Emp(员工号，姓名，姓别，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，部门号要求对照别一部门实体 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（）。
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心下悸者，______主之。
Why is(71)fun What delights may its practitioner espect his reward First is the sheer joy of making things.As the child delights in his mud pie,so the adult enjoys building things,especially things of his own design.Secong is the pleasure of making things that are useful to other people.Third is the fascinanon of fashioning complex puzzle-like objects of interlocking moving parts and watching them work in subtle eyeles,playing out the consequences of principies built in from the beginning.Fourth is the joy of always learning,which springs from the(72)nature of the task.In one way or another the problem is ever new,and its solver learns something:sometimes(73),sometimes theoretical,and sometimes both.Finally,there is the delight of working in such a tractable medium.The(74),like the poet,works only slightly removed from nure thought-stuff.Few media of ereation are so flexible,so easy to polish and rework,so readily capable of realizing grand conceptual structures. Yet the program(75),unlike the poet’s words,is real in the sense that it moves and works,producing visible outputs separate from the comstrct itself.It prints results,draws pictures,produces sounds,moves arms.Progamming then is fun because it gratifies creative longings built deep within us and delights sensibities we have in common with all men. （71）处填（）。
下列网络互连设备中，属于物理层的是（66），属于网络层的是（67） （67）处填（）。
已知一个二叉树的先序遍历序列为① 、② 、③ 、④ 、⑤ 中序遍历序列为② 、① 、④ 、③ 、⑤ ，则该二叉树的后序遍历序列为（57），对于任意一棵二叉树，叙述错误的是（58）。 （58）处填（）。
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