某公司网上销售管理系统的数据库部分关系模式如下所示。其中,客户号唯一标识一位客户,产品号唯一
客户(客户号,姓名,性别,地址,邮编)
产品(产品号,名称,库存,单价)
订单(订单号,时间,金额,客户号)
订单明细(订单号,产品号,数量)
订单关系模式的主键为(40);订单明细关系模式的主键为(41);其中订单的外键为(42)。
A.订单号
B.客户号
C.(订单号,客户号)
D.(订单号,时间)
客户(客户号,姓名,性别,地址,邮编)
产品(产品号,名称,库存,单价)
订单(订单号,时间,金额,客户号)
订单明细(订单号,产品号,数量)
订单关系模式的主键为(40);订单明细关系模式的主键为(41);其中订单的外键为(42)。
A.订单号
B.客户号
C.(订单号,客户号)
D.(订单号,时间)
A、在学生表上按学号建索引
B、在成绩表上按课程号建索引
C、在课程表上按课程号建索引
D、在学生表上按姓名建索引
A.0.0.0.120
B.0.0.12.120
C.0.0.12.0
D.0.252.12.120
One study conducted by a psychologist(121)of interviewing workers before and after the installation of a robot. The robot was used to control a matching process of stamping and assembling metal parts. Prior to installation, much of the work done by skilled machinists. After installation, the robot did the work, but the workers controlled the robot through the robot through a control panel. The results of the study indicated that the workers praised the robot(122)eliminating the physical labor and fatigue(123)the manual operation, but complained of more and continued stress. Prior to installation of the robot, there was time for talking or short periods of relaxation between jobs. Now, however, because of the speed of the robot, there was a need for constant scanning and monitoring of the operation(124)performed by the robot has the installation of the robot created a better work environment? Has the change from physical labor to mental stress resulted in an improved(125)of life? Much additional research is necessary.
A.Of
B.consisted
C.for
D.being
TCP functions at the Open System Interconnection(OSI)(61)layer, or Layer 4. Its chief responsibility is to ensure(62)end-to-end connectivity. IP, located one layer down, at the OSI network layer, or Layer 3, communicates the addresses of each(63)sender and receiver to the routers along the way. Routers and Layer 3 switches can read IP and other Layer 3(64). This information, combined with routing tables and other network intelligence, is all it takes to get(65)the room or around the world via TCP/IP.
A.transpose
B.translate
C.transmit
D.transport
A.FM(调频)和Wave Table(波表)
B.FM(调频)和AM(调幅)
C.AM(调幅)和Wave Table(波表)
D.FM(调频)和功率放大
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