2017年上半年数据库系统工程师考试上午真题（参考答案）

以下路由策略中，依据网络信息经常更新路由的是 （ ）。

The beauty of software is in its funciion ,in its internal srurcture,and in zhe way inwhich it is created by a team. To a user，a program with just the right features presented through an intuitive and （ ） interface is beautiful.To a soware designer，an intemal sucre that is partitioned in a simple and intuitive manner，and that minirnÍzes intemal coupling is beautiful.To developers and managers ，a motivated tenof developers makingignificant progress eve week，and producing defect-free code，is beautifu l. There is beauty on all these levels.

 Our world needs software -- 10ts of syears ago soware was something

that ran in a few big and expensive machines.   years ago it was something that ran in most companies and industrial settings. Now there is sware running in our cell phones ， watches ，appliances，automobi1es ，toys，and tools. And need for new and betler soware never （ ） As our civilization grows and expands，as developirig nations build their masuctures，as deve10ped nations striveωachieve ever greater efficiencies，the need for more and more software （ ）to increase. It would be a great shame if，in all that soware，there was no beauty.

We know that soware can be uglWe know that it can be hard to use，unreliable ，and carelessly structured. We know that there are software systems whose tangled and careless intemal structures make them expensive and difficult to change. We know that there are soware systems that present their features through an awkward and cumbersome interface.We know that there are software systems that crash and misbehave. These are （ ） systems. Unfortunately ，as a profession ，soware developers tend to create more ugly systems than beautiful ones.

There is a secret at the best sofuλrare developers know. Beauty is cheaper than ugliness. Beauty is faster than ugliness. A beautiful soware system can be built and maintained in less time，and for less money，than an ugly one. Novice soware developers don't understand is. They think that they have to do everything fast and quick.They think that beauty is （ ）. No! By doing things fast and quick，they make messes that make the software stiff and hard to understand. Beautiful systems are flexible and easy to understand. Building them and maintaining them is a joy. It is ugliness that is impractical.Ugliness will slow you down and make your software expensive and brittle. Beautiful systems cost the least to build and maintain ，and are delivered soonest.

以下IP 地址中，属于网络 10.110.12.29/255.255.255.224 的主机 IP 是（ ）。

在异步通信中，每个字符包含1位起始位、7 位数据位和2 位终止位，若每秒钟传送 500个字符，则每秒有效数据速率为（ ） 。

下面关于Linux 目录的描述中，正确的是（ ）。

在浏览器地址栏输入一个正确的网址后，本地主机将首先在（ ）中查询该网址对应的 IP地址。

数据挖掘中分类的典型应用不包括（ ）。（ ）可以用于数据挖掘的分类任务。

以下是平行数据库的四种体系结构，在（ ）体系结构中 所有处理器共享一个公共的主存储器和磁盘。

数据仓库中的数据组织是基于（ ）模型的。

CAP 理论是 NoSql理论的基础，下列性质不属于 CAP 的是（ ）。

NULL 值在数据库中表示（ ），逻辑运算UNKNOWN OR TRUE 的结果是（ ）。

某销售公司需开发数据库应用系统管理客户的商品购买信息。该系统需记录客户的姓名、出生日期 、年龄和身份证号信息，记录客户每次购买的商品名称和购买时间等信息。如果在设计时将出生日期和年龄都设定为客户实体的属性，则年龄属于（ ），数据库中购买记录表中每条购买记录对应的客户必须在客户表中存在，这个 约束属于（ ）。

给定关系模式R，其中属性集 U={A，B，C，D，E，G ，H} 函数依赖集F= {A→B，AE→H，BG→DC，E→C，H→E } ，下列函数依赖不成立的是（ ）