Which statement is true about the loss of system-critical data files in ARCHIVELOG mode？（）

单项选择题You executed the following command to start the database：  SQL> STARTUP  ORACLE instance started.  Total System Global Area 281018368 bytes  Fixed Size 789000 bytes  Variable Size 229635576 bytes  Database Buffers 50331648 bytes  Redo Buffers 262144 bytes ORA-00205： error in identifying controlfile， check alert log for more info  Which view would you query at this stage to investigate this missing control file？（）

A.V$INSTANCE
B.V$CONTROLFILE
C.DBA_CONTROL_FILES
D.V$DATABASE_PROPERTIES
E.V$CONTROLFILE_RECORD_SECTION

多项选择题Inyourdatabase，theLogWriter（LGWR）processisunabletowritetoamemberofacurrentredologgroupduetoread writefailure.Whichtwoeffectswouldyouseeinyourdatabase？（）

A.The database instance aborts.
B.The database operation temporarily halts till the member becomes available.
C.Writing proceeds as normal. LGWR writes to the available members of a group and ignores the unavailable members.
D.The member would be marked as STALE and an error message would be written to the alert log file and LGWR trace file.
E.The status of the group changes to INACTIVE and an error message would be written to the alert log file and LGWR trace file.

多项选择题WhichthreepiecesofinformationaretobemandatorilyprovidedwhilecreatinganewlistenerusingEnterpriseManagerDatabaseControl？（）

A.the port used by the listener
B.the protocol used by the listener
C.the server name where the listener runs
D.the log file and trace file destination for the listener
E.the database services to be registered with the listener

单项选择题Theapplicationworkloadonyourdatabaseissamebetween10a.m.and11a.m.onweekdays.Suddenlyyouobservepoorperformancebetween10a.m.and11a.m.inthemiddleoftheweek.Howwouldyouidentifythechangesinconfigurationsettings，workloadprofile，andstatisticstodiagnosethepossiblecausesoftheperformancedegradation？（）

A.by using the SQL access advisor
B.by using the Automatic Workload Repository report
C.by running the Automatic Database Diagnostic Monitor （ADDM）
D.by using the Automatic Workload Repository Compare Period report
E.by analyzing the output of the V$ACTIVE_SESSION_HISTORY view

多项选择题Whichtwostatementsaretrueaboutabitmapindex？（）

A.It is recommended for the columns that have unique values.
B.It can be converted to a B-tree index by using the ALTER INDEX command.
C.It has a bitmap segment for each distinct value in the key column， containing a string of bits in which each bit represents the presence or absence of a key column value.
D.Updating the key column locks the whole bitmap segment that contains the bit for the key value to be updated.