You need to ensure that the database users should be able to use the various flashback query features in order to go back in time by four hours. What would you do to achieve this?()
Aset SQL_TRACE=True
Bset UNDO_RETENTION=14400
Cset FAST_START_MTTR_TARGET=240
Dset LOG_CHECKPOINT_INTERVAL=240
Eset DB_FLASHBACK_RETENTION_TARGET=14400
Fset the RETENTION GUARANTEE clause for the undo tablespace
如果文件系统中有两个文件重名,不应采用()。
A、单级目录结构
B、树型目录结构
C、二级目录结构
D、A和C
Which object may be used during query optimization to improve the performance for a subset of SELECT queries?()
A、MQT
B、Trigger
C、Read Only Cursor
D、Stored Procedure
打开工作簿文件EXC.xlsx(内容同第2套电子表格题(2)中的EXC.xlsx文件),对工作表“选修课程成绩单”内的数据清单的内容进行分类汇总(提示:分类汇总前先按主要关键字“课程名称”升序排序),分类字段为“课程名称”,汇总方式为“平均值”,汇总项为“成绩”,汇总结果显示在数据下方,将执行分类汇总后的工作表还保在EXC.xlsx工作簿文件中,工作表名不变。
After you back up /export using a file system snapshot, and you have removed the snapshot, you also need to remove the backing store. If the snapshot was created with: # mkdir /var/tmp/backup-snaps # fssnap -o bs=/var/tmp/backup-snaps /export Which file do you need to remove? ()
A、 A
B、 B
C、 C
D、 D
A UDT is a data type which:()
A、must contain unique values.
B、cannot be CAST to other data types.
C、is created using the CREATE DISTINCT command.
D、contains a value that was automatically calculated from values in other columns.