在SQL*PLUS中显示EMP表结构的命令是()
A、LIST EMP
B、DESC EMP
C、SHOW DESC EMP
D、STRUCTURE EMP
E、SHOW STRUCTURE EMP
在SQL*PLUS中显示EMP表结构的命令是()
A、LIST EMP
B、DESC EMP
C、SHOW DESC EMP
D、STRUCTURE EMP
E、SHOW STRUCTURE EMP
What is the role of route preference?()
A、It is used as a tie breaker when the same prefix is available through multiple sources
B、It is used to determine which routes to accept into the routing table
C、It is used to select the best route between multiple equal-cost paths
D、It is used to select which routing table to use for forwarding
以下选项中不合法的标识符是( )。
A、print
B、FOR
C、&a
D、_00
For security reasons, an administrator is asked to modify the system to prevent someone from leaving a terminal logged in. To enable a five minute timeout for all users, what would need to be done to accomplish this task?()
A、Add the following line to /etc/environment: TMOUT=300
B、Add the following lines to /.profile TMOUT=5 export TMOUT
C、Execute the following command: chuser -u ALL -a TIMEOUT=5M
D、Execute the following command: chsec -u ALL -a TIMEOUT=600
A remote user is trying to telnet to the production server. The session is getting a timeout error. Which command should the user issue to verify the network connection?()
A、iptrace
B、nslookup
C、netstat
D、traceroute
()像表一样由列组成,其查询方式与表相同,但是不包含数据。
A、同义词
B、视图
C、索引
D、过程