执行查询文件myquery.qpr的命令是( )。
A、DO myquery
B、DO myquery.qpr
C、DO QUERY myquery
D、RUN QUERY myquery
Using the LIST command in Recovery Manager (RMAN), which two pieces of information in the RMANrepository can be listed?()
Astored scripts in the recovery catalog
Bbackups that can be deleted from disk
Cbackup sets and image copies are obsolete
Dbackups that do not have the AVAILABLE status in the RMAN repository RMAN
在笛卡儿坐标系中,当X轴的正向向左,Y轴和正向向上,那么Z轴的正向应向外。
A、对
B、错
在执行语句SELECT department_id FROM employees,departments WHERE employees.department_id= departments.department_id;时报错,原因是()。
A、没有给表employees和表departments加别名
B、没有给列department_id加别名
C、不能用employees.department_id=departments.department_id作为条件
D、SELECT后面的department_id没有指定是哪个表
简述色彩计划的特性。
在堆栈类SharedStack的定义中,为了保证堆栈在并发操作中数据的正确性,应在下划线处填入的修饰符是( )。(两个下划线的填写内容相同)public class SharedStack { ______ int idx = 0; ______ char[] data = new char[10]; public synchronized void push(char c){……} public synchronized void pop(){……}}
A、public
B、不使用修饰符
C、private
D、protected