问题 问答题

[说明]
某图书管理系统的主要功能是图书管理和信息查询。对于初次借书的读者,系统自动生成读者号,并与读者基本信息(姓名、单位和地址等)一起写入读者文件。
该系统的图书管理功能主要分为购入新书、读者借书、读者还书及图书注销4个方面。
(1)购入新书时需要为该书编制入库单。入库单内容包括图书分类目录号、书名、作者、价格、数量和购书日期,将这些信息写入图书目录文件并修改文件中的库存总量(表示到目前为止,购入此种图书的数量)。
(2)读者借书时需填写借书单。借书单内容包括读者号和所借图书分类目录号。系统首先检查该读者号是否有效,若无效,则拒绝借书;若有效,则进一步检查该读者已借图书是否超过最大限制数(假设每位读者能同时借阅的书不超过10本),若已达到最大限制数,则拒绝借书;否则允许借书,同时将图书分类目录号、读者号和借阅日期等信息写入借书文件中。
(3)读者还书时需填写还书单。系统根据读者号和图书分类目录号,从借书文件中读出与该图书相关的借阅记录,标明还书日期,再写回到借书文件中,若图书逾期,则处以相应的罚款。
(4)注销图书时,需填写注销单并修改图书目录文件中的库存总量。
系统的信息查询功能主要包括读者信息查询和图书信息查询。其中,读者信息查询可得到读者的基本信息及读者借阅图书的情况;图书信息查询可得到图书基本信息和图书的借出情况。
该图书管理系统的顶层数据流图,如图2-21所示;该图书管理系统的第0层DFD图,如图2-22所示;其中加工2的细化图,如图2-23所示。




[问题2]
该图书管理系统的第0层DFD图(见图2-22)有两条数据流是错误的,请指出改正后这两条数据流的起点、终点和数据流名称。

答案

参考答案:[问题2]
这是一道要求读者掌握DFD父图与子图的平衡原则和输入/输出平衡原则的综合分析题。本题的解答思路如下。
①根据DFD父图与子图的平衡原则和输入/输出平衡原则,通过比对图2-21和图2-22中所有输入数据流和输出数据流可知,如图2-22所示中与加工“1处理管理请求”相关的两条输入数据流和两条输出数据流都是正确的。其中,如图2-21所示中数据流“非法请求信息”在如图2-22所示中包含了“非法管理工作请求单”和“非法查询请求信息”两条子数据流。
②由题干给出的关键信息“对于初次借书的读者,系统自动生成读者号,并与读者基本信息(姓名、单位和地址等)一起写入读者文件”可知,加工“3登记读者信息”将有一条“读者情况”数据流输出到数据存储“读者文件”,即加工3是用来登记读者信息,应该将登记的读者信息写入读者文件,因此,在如图2-22所示中这一“写入”的箭头方向画反了。这条改正后数据流的起点是“3 登记读者信息”,终点是“读者文件”,数据流名称是“读者情况”。其中,该数据流名称应综合考虑题干中关键信息“系统自动生成读者号,并与读者基本信息一起写入读者文件”,并从如图2-22所示中数据流“读者信息”、“读者情况”中得到启发。
③由题干给出的关键信息“系统首先检查该读者号是否有效,若无效,则拒绝借书;若有效……”和“系统的信息查询功能主要包括读者信息查询和图书信息查询。其中读者信息查询可得到读者的基本信息及读者借阅图书的情况……”,并结合加工2的细化图(见图2-23)中加工“2.1读者信息查询”与数据存储“读者文件”之间数据流的箭头方向可知,加工“2处理查询请求”应该从数据存储“读者文件”中读出读者的信息,因此在如图2-22所示中这一“查询”的箭头画反了。这条改正后的数据流的起点是“读者文件”,终点是“2处理查询请求”,数据流名称是“读者情况”。其中,该数据流名称可从图2-22所示中加工“2处理查询请求”的输出数据流“读者情况”中得到启发。

阅读理解

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中由两项为多余选项。

Are you truly happy? Do you ever know what it means to be happy and what it takes to achieve happiness?小题1:The following are a few tips that I follow to create happiness in my life.

lMake a plan for achieving goals that you believe will make you happy. Your moods will very likely increase if you are going after something you value.

lSurround yourself with happy people. It is easy to begin to think negatively(消极地) when you are surrounded by people who think that way.小题2:

lWhen something goes wrong, try to figure out a solution instead of being absorbed in self pity. Truly happy people don’t allow setbacks(挫折) to affect their mood because they know that with a little thought they can turn the things back to their favor.

l小题3:These few minutes will give you the opportunity to focus on the positive things in your life and will lead you to continuous happiness.

l小题4:Whether you treat yourself to lunch, take a long, relaxing bath or simply spend a few extra minutes on your appearance, you will be subconsciously(下意识地) putting yourself in a better mood.

lFinding the humor in situations can also lead to happiness. Find a way to make light of a situation that would otherwise make you happy.

lKeeping healthy is another way to achieve happiness. 小题5:

A.What makes one person happy may be very different from what makes someone else happy.

B.On the contrary, if you are around people who are happy, their emotional state will be easily passed to you.

C.Being overweight or not eating foods containing nutrition have a negative effect on your mood.

D.These are important questions for anyone who is seeking happiness to ask themselves.E.Spend a few minutes each day thinking about the things that make you happy.

F.There are some tips in life that lead to happiness.

G.It’s also important to take some time each day to do something nice for yourself.

单项选择题