单选题You are attempting to clear an unarchived redo log file. In order to manually enact a log switch, which of the following statements is appropriate?（）A ALTER DATABASE B ALTER SYSTEM C ALTER USER D ALTER REDO LOG

第1题：

第2题：

Your database is in ARCHIVELOG mode. You have two online redo log groups, each of which contains one redo member. When you attempt to start the database, you receive the following errors: ORA-00313: open failed for members of log group 1 of thread 1 ORA-00312: online log 1 thread 1: 'D:/REDO01.LOG' You discover that the online redo log file of the current redo group is corrupted. Which statement should you use to resolve this issue?（）

• A、ALTER DATABASE DROP LOGFILE GROUP 1;
• B、ALTER DATABASE CLEAR LOGFILE GROUP 1;
• C、ALTER DATABASE CLEAR UNARCHIVED LOGFILE GROUP 1;
• D、ALTER DATABASE DROP LOGFILE MEMBER 'D:/REDO01.LOG

第3题：

第4题：

The database is running in the ARCHIVELOG mode. It has three redo log groups with one member each. One of the redo log groups has become corrupted. You have issued the following command during the recovery of a damaged redo log file：   ALTER DATABASE CLEAR UNARCHIVED LOGFILE GROUP 3；   Which action should you perform immediately after using this command？（）  

• A、 You should perform a log switch
• B、 You should make a backup of the database
• C、 You should switch the database to the NONARCHIVELOG mode
• D、 You should shut down the database instance and perform a complete database recovery

第5题：

If a log file becomes corrupted， it may cause the database to stall. How would you correct such a situation？（）  

• A、 Recover the online redo log from backup.
• B、 Delete and re-create the log file.
• C、 Use the alter database clear logfile command to clear the log file.
• D、 Shut down the database and restart it.
• E、 Shut down the database and then mount it. Clear the log file with the alter database clear logfile command and then restart the database with alter database open resetlogs.

第6题：

Redo log files are not multiplexed in your database. Redo log blocks are corrupted in group 2， and archiving has stopped. All the redo logs are filled and database activity is halted. Database writer has written everything to disk. Which command would you execute to proceed further？（）

• 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；

第7题：

User SCOTT wants to back out the transactions on the REGIONS table in his schema. As a DBA, which commands must you execute to enable SCOTT to flash back the transactions?（）

• A、ALTER DATABASE FLASHBACK ON;
• B、GRANT SELECT any transaction TO scott;
• C、GRANT EXECUTE ON dbms_flashback TO scott;
• D、ALTER DATABASE ADD SUPPLEMENTAL LOG DATA;
• E、ALTER TABLESPACE undots1 RETENTION GUARANTEE;
• F、ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS;

第8题：

第9题：

Upon starting your database， you receive the following error：   SQL> startup ORACLE instance started.  Total System Global Area 171581440 bytes Fixed Size 1298640 bytes Variable Size 146804528 bytes Database Buffers 20971520 bytes Redo Buffers 2506752 bytes Database mounted.  ORA-00313： open failed for members of log group 1 of thread 1  ORA-00312： online log 1 thread 1： ’/oracle01/oradata/orcl/redo01.log’ ORA-00312： online log 1 thread 1： ’/oracle01/oradata/orcl/redo01a.log’   You can choose from the following steps：   a. Restore the database datafiles.  b. Issue the alter database clear unarchived logfile group 1 command. c. Issue the alter database open command.  d. Issue the alter database open resetlogs command.  e. Recover the database using point-in-time recovery. f. Issue the Startup Mount command to mount the database.  g. Back up the database.  Which is the correct order of these steps in this case？（）

• A、a， f， e， d， g
• B、f， e， d
• C、f， b， c， g
• D、a， f， c
• E、The database cannot be recovered.

第10题：

如何强制执行日志切换（）

• A、ALTER SYSTEM CHECKPOINT;
• B、ALTER SYSTEM CHECKPOINT FORCE;
• C、ALTER SYSTEM SWITCH LOGFILE;
• D、ALTER SYSTEM SWITCH LOGFILE FORCE;
• E、ALTER DATABASE LOG SWITCH;