单选题软件测试是为了发现错误而执行程序的过程。检验软件是否满足用户需求的测试称为______。 A.系统测试 B.组装测试 C.确认测试 D.回归测试
单选题当X,Y之间是1对多联系时,则存在函数依赖 (36) ;给定函数依赖f:X—>Y和g:X—>Y,则 (37) 。
单选题在数据库概念设计的过程中,视图设计—般有三种设计方式,以下各项中不对的是 (44) 。
单选题事务有多种性质,“一旦事务成功提交,即使数据库崩溃,其对数据库的更新操作也将永久有效。”这一性质属于事务的( )性质。
单选题在各种多媒体压缩编码技术中,简单而言, (49) 就是把高频率的数据用短码来表示,而频率低的就用相对长的编码来表示。
单选题若视频图像每帧的数据量为6.4MB,帧速率为30帧/秒,则显示10秒的视频信息,其原始数据量为 (14) MB。 A.64 B.192 C.640 D.1920
单选题给定关系 R(A,B,C,D)和关系 S(A,C,D,E,F),对其进行自然连接运算 R??S后的属性列为( )个;与R.C>S.F(R??S)等价的关系代数表达式为( )
单选题进程Pl.P2.P3.P4和P5的前趋图如下图所示:
若用PV操作控制进程P1.P2.P3.P4和P5并发执行的过程,则需要设置5个信号量S1.S2.S3.S4和S5,且信号量SI~S5的初值都等于零。下图中a和b处应分别填写( );c和d处应分别填写( ),e和f处应分别填写( )
。
单选题E-R 图中的组合属性应转换为对象-关系数据模型中的 (62) 。
单选题SMTP传输的邮件报文采用______格式表示上。
单选题Currently the Pentium chip or (71) , made by (72) , is the most common CPU though there are many other companies that produce processors for personal computers. One example is the CPU made by Motorola which is used in Apple computers. With faster processors the clock speed becomes more important. Compared to some of the first computers which operated at below 30 megahertz ( (73) ) the Pentium chips began at 75 megahertz in the late 1990g. As of mid 2003 speeds now exceed 3000 + megahertz or 3 gigahertz (check your local computer store for the latest speed) . It depends on the (74) that the chip is housed in, or the (75) , as to whether you are able to upgrade to a faster chip. The motherboard contains the circuitry and connections that allow the various component to communicate with each other.
单选题需求分析阶段要生成的文档是 (53) 和数据字典。
单选题( )是构成我国保护计算机软件著作权的两个基本法律文件
单选题如果系统采用信箱通信方式,当进程调用Send原语被设置成“等信箱”状态时,其原因是______。
单选题以下关于程序设计语言的叙述中,错误的是______。
单选题 ARP协议属于{{U}} {{U}} 66 {{/U}}
{{/U}}协议,它的作用是{{U}} {{U}} 67 {{/U}} {{/U}}。
单选题Basically,a firewall if a ______ process or a set of integrated processes that runs on a router or______ to control the flow of networked application traffic!______ through it.Typically,firewallsare placed on the entry point to a ______ network such as the Internet.They could be consideredtraffic cops.The firewall"s ______ is to ensure that all communication between an organization"snetwork and the intemet conform to the organization"s security policies.
单选题给定关系模式销售排名(员工号,商品号,排名),若每一名员工每种商品有一定的排名,每种商品每一排名只有一名员工,则以下叙述中错误的是_______。
单选题分段管理的主要优点是: (23) 。