题目内容

关于分布式数据库,下列说法错误的是( )。

A. 分布式数据库的查询代价需要考虑站点间数据传输的通信代价,一般来说导致数据传输量大的主要原因是数据间的连接操作和并操作
B. 分布式数据库中位置透明性是指数据分片的分配位置对用户是透明的,使得用户在编程时只需考虑数据分片情况,而不用关心具体的分配情况
C. 分布式数据库的事务管理包括恢复控制和并发控制,恢复控制一般采用的策略是基于两阶段的提交协议
D. 分布式数据库系统的目标是利用多处理机结点并行地完成数据库任务,以提高数据库系统的整体性能

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数据库物理设计的目标是为应用数据提供合适的数据存储结构,同时要保证数据库系统具有良好的性能。关于数据库物理设计,下列说法中错误的是( )。

A. 数据库物理设计需要考虑数据的存储方式、存取路径和具体的实现细节,还需要考虑数据的加载方式
B. 数据库物理设计一般需要根据数据的存储需求和使用需求确定数据库管理系统的配置参数
C. 数据库物理设计需要权衡系统的时间效率、空问效率、维护代价和各种用户要求,因此可能会产生多个备选方案
D. 在数据库物理设计后期,可以根据实际需要适当降低某些关系模式的规范化程度,以提高查询效率

下列关于Windows 2003系统DHCP服务器的描述中,错误的是( )。

A. DHCP服务器负责多个网段IP地址分配时,需要配置多个作用域
B. 客户机与DHCP服务器不在一个网段时,需DHCP中继转发DHCP消息
C. DHCP中继转发DHCP发现消息时,需修改该消息中的相关字段
DHCP中继转发客户机的消息时,仍使用广播方式发送给DHCP服务器

To absorb a younger work force, many companies offered retirement plans as incentives for older workers to retire and make way for the younger ones who earned lower salaries.

A. rewards
B. opportunities
C. motives
D. stimulus

阅读材料,回答题。 Deport them or notIn a country that defines itself by ideals,not by shared blood,who should be allowed to come,work and live here?In the wake of the Sept.1 1 attacks these questions have never seemed more pressing.On Dec.11,2001,as part of the effort to increase homeland security,federal and local authorities in 14 states staged“Operation Safe Travel”-raids on airports to arrest employees with false identification(身份证明).In Salt Lake City there were 69 arrests.But those captured were anything but terrorists,most of themillegal immigrants from Central or South America.Authorities said the undocumented workers’illegal status made them open to blackmail(讹诈)by terrorists.Many immigrants in Salt Lake City were angered by the arrests and said they felt as if they were being treated like disposable goods.Mayor Anderson said those feelings were justified to a certain extent,“We’re saying we want you to work in these places,we’re going to look the other way in terms of what our laws are,and then when it’s convenient for us,or when we can try to make a point in terms of national security,especially after Sept.1 1,then you’re disposable.There are whole families being uprooted for all of the wrong reasons,”Anderson said.If Sept.1 1 had never happened.the airport workers would not have been arrested and could have gone oil quietly living in America.probably indefinitely.Ana Castr0,a manager at a Ben&Jerry’s ice cream shop at the airport,had been workin9 10 years with the same false Social Security card when she was arrested in the December airport raid.Now she and her family are living under the threat of deportation(驱逐出境).Castro’s case is currently waiting to be settled.While she awaits the outcome,the government has granted her permission to work here and she has returned to her job at Ben&Jerry’s.According to the author,the United States claims to be a nation__________.

A. composed of people having different values
B. encouraging individual pursuits
C. sharing common interests
D. founded on shared ideals

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