当前位置:首页计算机类软件水平考试中级数据库系统工程师->下表为两个事务T1和T2的一个并发调度。其中,数据项A的初值

下表为两个事务T1和T2的一个并发调度。其中,数据项A的初值为3,B的初值为4;变量X、Y为事务中的局部变量。语句X=Read(A)表示读取数据项A的值到变量X,Write(A,X)表示将变量X的值写入数据项A中。此并发调度执行结束后A和B的值分别为A=7,B=6;该调度( )。

中级数据库系统工程师,历年真题,2022年上半年(上午)《数据库系统工程师》真题

  • A.是正确的
  • B.是可串行化的
  • C.是不正确的
  • D.会产生死链
答案: C
本题解析:

运行过程如下图所示,最终A=7,B=6,该调度是不可串行化的。

中级数据库系统工程师,历年真题,2022年上半年(上午)《数据库系统工程师》真题

更新时间:2023-06-12 14:35
纠错

你可能感兴趣的试题

单选题

The Internet of( 1)(IoT) describes physical objects that are embedded with Sensor,processing abilities,softwares,and other technologies that connect with other devices and systems over the ( 2) or other communication and exchange data networks .Over the past few years, IoT has become one of the most important technologies of the ( 3 ) centuryWe can connect objects to the Internet via embedded devices. By means of( 4) computing, the cloud, big data, and mobile technologies, physical things can share and collect data with minimal human intervention. Traditional fields of embedded systems,wireless ( 5) networks (WSNs),control systems,automation, independently and collectively enable IoT.回答5处

  • A.sensor
  • B.searching
  • C.service
  • D.source
查看答案
单选题

The Internet of( 1)(IoT) describes physical objects that are embedded with Sensor,processing abilities,softwares,and other technologies that connect with other devices and systems over the ( 2) or other communication and exchange data networks .Over the past few years, IoT has become one of the most important technologies of the ( 3 ) centuryWe can connect objects to the Internet via embedded devices. By means of( 4) computing, the cloud, big data, and mobile technologies, physical things can share and collect data with minimal human intervention. Traditional fields of embedded systems,wireless ( 5) networks (WSNs),control systems,automation, independently and collectively enable IoT.回答4处

  • A.low-level
  • B.low-cost
  • C.high-cost
  • D.high-performance
查看答案
单选题

The Internet of( 1)(IoT) describes physical objects that are embedded with Sensor,processing abilities,softwares,and other technologies that connect with other devices and systems over the ( 2) or other communication and exchange data networks .Over the past few years, IoT has become one of the most important technologies of the ( 3 ) centuryWe can connect objects to the Internet via embedded devices. By means of( 4) computing, the cloud, big data, and mobile technologies, physical things can share and collect data with minimal human intervention. Traditional fields of embedded systems,wireless ( 5) networks (WSNs),control systems,automation, independently and collectively enable IoT.回答3处

  • A.19th
  • B.20th
  • C.21th
  • D.22th
查看答案
单选题

The Internet of( 1)(IoT) describes physical objects that are embedded with Sensor,processing abilities,softwares,and other technologies that connect with other devices and systems over the ( 2) or other communication and exchange data networks .Over the past few years, IoT has become one of the most important technologies of the ( 3 ) centuryWe can connect objects to the Internet via embedded devices. By means of( 4) computing, the cloud, big data, and mobile technologies, physical things can share and collect data with minimal human intervention. Traditional fields of embedded systems,wireless ( 5) networks (WSNs),control systems,automation, independently and collectively enable IoT.回答2处

  • A.path
  • B.Internet
  • C.route
  • D.switch
查看答案
单选题

The Internet of( 1)(IoT) describes physical objects that are embedded with Sensor,processing abilities,softwares,and other technologies that connect with other devices and systems over the ( 2) or other communication and exchange data networks .Over the past few years, IoT has become one of the most important technologies of the ( 3 ) centuryWe can connect objects to the Internet via embedded devices. By means of( 4) computing, the cloud, big data, and mobile technologies, physical things can share and collect data with minimal human intervention. Traditional fields of embedded systems,wireless ( 5) networks (WSNs),control systems,automation, independently and collectively enable IoT.回答1处

  • A.this
  • B.thing
  • C.think
  • D.things
查看答案
单选题

管理员要检查本地主机TCP/IP协议是否能够正常工作,应使用下面( )命令。

  • A.ping 127.0.0.1
  • B.nslookup 127.0.0.1
  • C.ftp 127.0.0.1
  • D.ipconflg 127.0.0.1
查看答案
单选题

在Windows系统中,可以在“运行”对话框中使用( )打开命令行窗口。

  • A.command
  • B.cmd
  • C.run
  • D.do
查看答案
单选题

在Windows 系统中,要持续ping某主机,应使用( )选项。

  • A.-t
  • B.-a
  • C.-n
  • D.-s
查看答案
单选题

在Linux系统中,管理员在DHCP服务器的配置文件中添加了下面一段代码:subnet 192.168.20.0 netmask 255.255.255.0{range 192 .168 .20 .10 192 .168 .20.50;option domain-name-server ns1 .internal.example.comoption routers 192 .168 .20.254;option broadcast-address 192.168.20.255;default-lease-time 1200;max-lease-time 360000;}当该DHCP服务器启动后,下面分配给客户端的IP地址中,正确的是( ).

  • A.192 .168.20.0
  • B.192.168.20.254 192.168.20.254
  • C.192.168.20.255
  • D.192.168.20.11
查看答案
单选题

在Linux系统中,通常使用( )为用户提供FTP服务,其配置信息存放在(回答此处)目录中。

  • A./etc
  • B./dev
  • C./root
  • D./boot
查看答案