One of the user sessions was terminated abnormally in the middle of a transaction. What does Oracle database do to recover it？（）

单项选择题Initially， for the Automatic Workload Repository （AWR） statistics， the retention period is set to 7 days， the collection interval is set to 30 minutes and the collection level is set to Typical in your production database.  You have been using the Memory Advisor for the last three months to generate recommendations for tuning memory components. However， when you observe the Memory Advisor on a Friday， you find that the statistics are available only for two days， Thursday and Friday， of that week.  What would have caused the statistics to be removed？（）

A.On Wednesday， the statistics have been purged.
B.On Wednesday， the retention period has been set to zero.
C.On Wednesday， the collection interval has been set to zero.
D.On Wednesday， the collection level has been changed to All.
E.On Wednesday， the retention period has been set to one day.
F.On Wednesday， the retention period has been set to two days.
G.On Wednesday， the collection level has been changed to Typical.
H.On Wednesday， the collection interval has been set to 1440 minutes.

单项选择题You execute the following set of commands to create a database user and to grant the system privileges in your production environment.  SQL> CREATE USER user01  IDENTIFIED BY oracle DEFAULT TABLESPACE tbs1  TEMPORARY TABLESPACE temp PROFILE default    SQL> GRANT create session， create table TO user01； While executing the command to create a table， the user gets the following error message and the CREATE TABLE.. command fails.  ERROR at line 1： ORA-01950： no privileges on tablespace  What could be the possible reason for this error message？（）

A.The tablespace TBS1 is full.
B.The user is not the owner of the SYSTEM tablespace.
C.The user does not have quota on the TBS1 tablespace.
D.The user does not have sufficient system privileges to create table in the TBS1 tablespace.
E.The user does not have sufficient privileges to create table on the default permanent tablespace.

单项选择题Redologfilesarenotmultiplexedinyourdatabase.Redologblocksarecorruptedingroup2，andarchivinghasstopped.Alltheredologsarefilledanddatabaseactivityishalted.Databasewriterhaswritteneverythingtodisk.Whichcommandwouldyouexecutetoproceedfurther？（）

A.RECOVER LOGFILE BLOCK GROUP 2；
B.ALTER DATABASE DROP LOGFILE GROUP 2；
C.ALTER DATABASE CLEAR LOGFILE GROUP 2；
D.ALTER DATABASE RECOVER LOGFILE GROUP 2；
E.ALTER DATABASE CLEAR UNARCHIVED LOGFILE GROUP 2；

单项选择题Youareusingthefollowingcommandtoclearthelogfilegroup：ALTERDATABASECLEARLOFFILEGROUP2；Inwhichcasewouldthecommandbesuccessful？（）

A.Group 2 is the active group.
B.Group 2 is the current group.
C.Database is in the MOUNT state.
D.Group 2 has been already archived.

单项选择题You are working on a very large database. You had performed a binary backup of the control file a month ago. After this you added a few tablespaces， and dropped a couple of tablespaces. This morning， due to hardware failure， you lost all your control files.  How would you recover the database from this situation？（）

A.A
B.B
C.C
D.D
E.E