【单选题】若事件A与召的交事件为不可能事件,则A与B一定是( ).
【多选题】Which two statements are true regarding undo tablespaces()
A.
The database can have more than one undo tablespace.
B.
The UNDO_TABLESPACE parameter is valid in both automatic andmanualundo management.
C.
Undo segments automatically grow and shrink as needed, acting as circular storage buffer for their assigned transactions.
D.
An undotablespaceis automatically created if the UNDO_TABLESPACEparameter is not set and the UNDO_MANAGEMENT parameter is set to AUTO during the database instance start up.
【单选题】利用一组三角板配合丁字尺,可画( )倍数角的斜线
【单选题】利用一组三角板配合丁字尺,可画( )倍数角的斜线
【单选题】若事件A、B之交为不可能事件,则A和B是( )。
【单选题】()时期的园林中已经有了成组的风景,既有土山又有池沼或台。