【单选题】“若a是实数,则︱a︱≥0”这一事件是 [ ]
【单选题】What is true if you want to switch undo tablespaces from the current one, called UNDO1, to a new one called UNDO2?()
A.
It is NOT possible to switch unless no active transaction exist in UNDO1.
B.
It is possible to switch to UNDO2; but current active transactions will abort.
C.
It is possible to switch to UNDO2; current active transactions will be automatically migrated to UNDO2.
D.
It is possible to switch to UNDO2; only current active transactions will continue to execute inside UNDO1.
【多选题】You require the Oracle server to manage the undo segments and space among various active sessions automatically. You created an undo tablespace, UNDO_TBS1, in your database. Which two additional steps...
A.
Set the UNDO_RETENTION parameter to 900 or more.
B.
Create an initial undo segment in the undo tablespace.
C.
Enable the retention guarantee for the undo tablespace.
D.
Set the UNDO_TABLESPACE parameter to UNDO_TBS1.
E.
Set the UNDO_MANAGEMENT initialization parameter to AUTO.
【单选题】主船体两舷舷侧在后部的线型弯曲部分称之为:
【单选题】若事件A是必然事件,事件B是不可能事件,则事件A与B的关系是( )
【简答题】在UNDO命令执行之后,立即键入什么命令可以将UNDO 命令取消重新执行一次 (A)ERASE (B)REDO (C)OOPS (D)REDRAW
【单选题】若a为实数,则“二次根式 a 2 ≥0 ”这一事件是( )