单选题You execute the following command in your Certkiller .com production database to change the width of the CUST_NAME column of the CUSTOMERS table： ALTER TABLE customers  MODIFY （cust_nameVARCHAR2 （40）） /  When you execute the command， it displays the fo

第1题：

You are working in an online transaction processing (OLTP) environment. You use the FLASHBACKTABLE command to flash back the CUSTOMERS table. Before executing the FLASHBACK TABLE command, the system change number (SCN) was 663571. After flashing back the CUSTOMERS table, you realize that the table is not in the correct state. Now, you need to reverse the effects of the FLASHBACK TABLE command. Which is the fastest and the most efficient option to reverse the effects of the FLASHBACK TABLE command?（）

• A、Restore the backup control file and open the database with RESETLOGS option.
• B、Perform point-in-time recovery because flashback cannot be performed again on this table
• C、Execute the FLASHBACK DATABASE statement to retrieve the CUSTOMERS table as it was at SCN 663571
• D、Execute another FLASHBACK TABLE statement to retrieve the CUSTOMERS table as it was at SCN 663571

第2题：

You work as a database administrator for Certkiller .com. Your database is in the MOUNT state and you execute the following command to open it ALTER DATABASE OPEN； What two actions are performed as a result of this command？（）

• A、All control files are opened
• B、All redo files are opened
• C、The password file is opened
• D、The parameter file is opened
• E、All online data files are opened

第3题：

Your database is running in the ARCHIVELOG mode. You have configured RMAN for backup and recovery operations. You execute the following command from the RMAN prompt：   RMAN> CONFIGURE CONTROLFILE AUTOBACKUP ON；   After executing this command， in which of the following cases will RMAN make an auto-backup of the control file？ （）

• A、 when you change the name of a datafile
• B、 when you drop a table from the database
• C、 when you take an export of the database
• D、 when you back up the database using OS utilities
• E、 when you issue an ALTER SYSTEM SWITCH LOGFILE statement
• F、 when you issue a BACKUP command from inside the RMAN run block

第4题：

One of the users in the PROD database， Adams， complains that his update on the table， TRANS， is taking an unusually long time to complete. You find that the table gets locked by another database user before Adams starts his transactions， and you are unable to contact the user holding the table lock. As Adams is updating some crucial rows in the table， he should get the highest priority. Which method would you use to overcome this problem？（）

• A、execute the command， ALTER SESSION KILL ..， to kill the blocking session
• B、execute the DBMS_SESSION.KILL_SESSION procedure to kill the blocking session
• C、execute the command， ALTER SYSTEM KILL SESSION ..， to kill the blocking session
• D、execute the command， ALTER SESSION UNLOCK ..， to release the lock for the blocking session
• E、execute the command， ALTER SYSTEM UNLOCK SESSION ..， to release the lock for the blocking session

第5题：

You are working in an online transaction processing （OLTP） environment. You used the FLASHBACK TABLE command to flash back the CUSTOMERS table. Before executing the FLASHBACK TABLE command， the System Change Number （SCN） was 663571. After flashing back the CUSTOMERS table， you realize that the table is not in the correct state and the resultant changes are not what you had desired. So， you need to reverse the effects of the FLASHBACK TABLE command while ensuring that：  a） No other user data in the database is affected.  b） The operation takes the minimum possible time.  Which option would you choose？（）

• A、use the ROLLBACK command with SCN 663571
• B、perform Flashback Transaction Query with SCN 663571
• C、execute the FLASHBACK DATABASE statement to retrieve the CUSTOMERS table as it was at SCN 663571
• D、execute another FLASHBACK TABLE statement to retrieve the CUSTOMERS table as it was at SCN 663571

第6题：

You work as a database administrator for Supportcenter.cn. Your database is in the MOUNT state and you execute the following command to open it ALTER DATABASE OPEN； What two actions are performed as a result of this command？（）

• A、All control files are opened
• B、All redo files are opened
• C、The password file is opened
• D、The parameter file is opened
• E、All online data files are opened

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第13题：

Which statement adds a constraint that ensures the CUSTOMER_NAME column of the CUSTOMERS table holds a value?（）

• A、ALTER TABLE customers ADD CONSTRAINT cust_name_nn CHECK customer_name IS NOT NULL;
• B、ALTER TABLE customers MODIFY CONSTRAINT cust_name_nn CHECK customer_name IS NOT NULL;
• C、ALTER TABLE customers MODIFY customer_name CONSTRAINT cust_name_nn NOT NULL;
• D、ALTER TABLE customers MODIFY customer_name CONSTRAINT cust_name_nn IS NOT NULL;
• E、ALTER TABLE customers MODIFY name CONSTRAINT cust_name_nn NOT NULL;
• F、ALTER TABLE customers ADD CONSTRAINT cust_name_nn CHECK customer_name NOT NULL;

第14题：

You execute the following command in your Certkiller .com production database to change the width of the CUST_NAME column of the CUSTOMERS table： ALTER TABLE customers  MODIFY （cust_nameVARCHAR2 （40）） /  When you execute the command， it displays the following error message：  ERROR at line 1：  ORA-00054： resource busy and acquire with NOWAIT specified  What could be the reason for the error message？（）

• A、The database instance is not available.
• B、The ALTER TABLE command does not have WAIT option
• C、The table or a row in the table is currently locked by another user session.
• D、The database instance is busy processing other user sessions commands.
• E、The CUSTOMERS table has no long running query active at the time when this request is made.
• F、The server process executing the ALTER TABLE command is busy with another command execution

第15题：

You execute the following command in your Supportcenter.cn production database to change the width of the CUST_NAME column of the CUSTOMERS table：  ALTER TABLE customers   MODIFY （cust_nameVARCHAR2 （40））   /   When you execute the command， it displays the following error message：   ERROR at line 1：   ORA-00054： resource busy and acquire with NOWAIT specified   What could be the reason for the error message？（）

• A、The database instance is not available.
• B、The ALTER TABLE command does not have WAIT option
• C、The table or a row in the table is currently locked by another user session.
• D、The database instance is busy processing other user sessions commands.
• E、The CUSTOMERS table has no long running query active at the time when this request is made.
• F、The server process executing the ALTER TABLE command is busy with another command execution

第16题：

Examine this command: SQL > exec DBMS_STATS.SET_TABLE_PREFS (‘SH’, ‘CUSTOMERS’, ‘PUBLISH’, ‘false’); Which three statements are true about the effect of this command?（）

• A、Statistics collection is not done for the CUSTOMERS table when schema stats are gathered.
• B、Statistics collection is not done for the CUSTOMERS table when database stats are gathered.
• C、Any existing statistics for the CUSTOMERS table are still available to the optimizer at parse time.
• D、Statistics gathered on the CUSTOMERS table when schema stats are gathered are stored as pending statistics.
• E、Statistics gathered on the CUSTOMERS table when database stats are gathered are stored as pending statistics.

第17题：

You work as a database administrator for Certkiller .com. Your database is opened in NOARCHIVEKLOG mode. You decide to place the database in ARCHIVELOG mode.  How would you do this？（）

• A、Execute the ALTER DATABASE ARCHIVELOG statement 
• B、Select ARCHIVELOG option in the database control and restart the database to apply the changes. 
• C、Shut down and start the instance, and in the NOMOUNT state execute the ALTER DATABASE ARCHIVELOG statement. 
• D、Shut down and start the instance, mount the database, then execute the ALTER DATABASE ARCHIVELOG statement. 

第18题：

You have lost all your database control files. To recover them， you are going to use the results of the alter database backup controlfile to trace command. Your datafiles and your online redo logs are all intact.  Which of the following is true regarding your recovery？（）  

• A、 You will need to open the database with the resetlogs command.
• B、 All you need to do is execute the trace file from SQL*Plus and it will perform the recovery for you.
• C、 You will use the resetlogs version of the create controlfile command.
• D、 You will use the noresetlogs version of the create controlfile command.
• E、 You will use the trace file to create a backup control file， and then you will recover the database with the recover database using backup controlfile command

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