单选题In your database， UNDO_RETENTION has been set to 600 sec and UNDO tablespace is configured for RETENTION GUARANTEE. Which statement regarding RETENTION GUARANTEE is true？ （）A Undo data is retained until the next full database backup.B No committed undo

第1题：

You are maintaining your database in Oracle10g. You set the value of the UNDO_RETENTION initialization parameter to zero in the initialization parameter file. What will be the impact of specifying this setting？（）  

• A、 The database will not start.
• B、 The database will start but will not retain the undo data in the undo segment.
• C、 The database will start， and the undo segment will contain the undo data for at least one hour.
• D、 The database will start， and the undo segment will retain the undo data for at least 15 minutes.

第2题：

You work as a database administrator for Certkiller .com. Users complain that their query is taking a long time to complete. You suspect the database buffer cache size to be the reason， and you define an alert to be generated when the buffer cache hit metric goes below 85%. When you observe the dynamic performance views， you find that the buffer cache hit ratio is 81% but no alerts are being generated.  What could be the reason for this problem？（）

• A、The advisory memory has been turned off.
• B、The DB_CACHE_ADVICE parameter has been set to OFF in the parameter file.
• C、The STATISTICS_LEVEL parameter has been set to BASIC in the parameter file.
• D、The TIMED_STATISTICS parameter has been set to FALSE in the parameter file.
• E、The STATISTICS_LEVEL parameter has been set to TYPICAL in the parameter file.

第3题：

第4题：

In your database，the LDAP_DIRECTORY_SYSAUTH initialization parameter has been set to YES and the users who need to access the database as DBAs have been granted SYSDBA enterprise role in Oracle Internet Directory （OID）. SSL and the password file have been configured. A user SCOTT with the SYSDBA privilege tries to connect to the database instance from a remote machine using the command：$ SQLPLUS scott/tiger@DB01 AS SYSDBA   where DB01 is the net service name.   Which authentication method would be used first？（）  

• A、 authentication by password file
• B、 authentication by using certificates over SSL
• C、 authentication by using the Oracle Internet Directory
• D、 authentication by using the local OS of the database server

第5题：

Your database is running under automatic undo management and the UNDO_RETENTION parameter is set to 900 sec. You executed the following command to enable retention guarantee：  SQL> ALTER TABLESPACE undotbs1 RETENTION GUARANTEE;  What effect would this statement have on the database？（）

• A、The extents in undo tablespace retain data until the next full database backup.
• B、The extents containing committed data in the undo tablespace are never overwritten.
• C、The extents which no longer contain uncommitted data in the undo tablespace are not overwritten for at least15 minutes.
• D、The extents containing committed data in the undo tablespace are not overwritten until the instance  is shut down.

第6题：

You are maintaining your database in Oracle10g. You find that the number of languages that should be supported in your database has increased. The character set of your database is UTF8. You decide to migrate your database to the AL16UTF16 national character set.   How will you migrate your database from UTF8 to AL16UTF16？（）  

• A、 by using the RMAN utility
• B、 by using the export/import utility
• C、 by using the ALTER DATABASE command
• D、 by enabling the change tracking feature

第7题：

You work as a database administrator for Certkiller .com. You want to create your database with the automatic undo management feature enable.Which two tasks must you perform to achieve this？（）

• A、Set the UNDO_RETENTION parameter to AUTO.
• B、Create an initial undo segment in undotablespace.
• C、Set the UNDO_RETENTION parameter to 900 or more
• D、Set the initialization parameter UNDO_MANAGEMENT to AUTO
• E、Set the UNDO_MANAGEMENT parameter to the name of an undotablespace

第8题：

In your database， the RESULT_CACHE_MODE parameter has been set to MANUAL in the initialization parameter file. You issued the following command：   SQL>SELECT /*+ RESULT_CACHE */ sale_category， sum（sale_amt） FROM sales  GROUP BY sale_category；   Where would the result of this query be stored（）？  

• A、 database buffer cache
• B、 shared pool
• C、 PGA
• D、 large pool

第9题：

You have been recently hired as a database administrator. Your senior manager asks you to study the production database server and submit a report on the settings done by the previous DBA.  While observing the server settings， you find that the following parameter has been set in the parameter file of the database：  REMOTE_OS_AUTHENT = TRUE  What could have been the reason to set this parameter as TRUE？（）

• A、to enable operating system authentication for a remote client
• B、to restrict the scope of administration to identical operating systems
• C、to allow the start up and shut down of the database from a remote client
• D、to enable the administration of the operating system from a remote client
• E、to disable the administration of the operating system from a remote client

第10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.