By mistake， you ran the batch job （for updating the BILL_DETAILS table） twice. You are not sure which rows in the BILL_DETAILS table were affected. You need to identify： 
a） a list of changes made along with the transaction identifier of each change 
b） the necessary SQL statements to undo the erroneous changes 
Which option would you choose？（） 

单项选择题View the Exhibits. You performed operations on the DEPT4 table as shown in the Exhibit. When you perform the FlashbackVersions Query， you find that the first two updates are not listed. What could be the reason？（）

A.The row movement is not enabled on the table.
B.The first two updates were not explicitly committed.
C.The Flashback Versions Query lists only the most recent update.
D.The Flashback Versions Query stops producing rows after it encounters a time in the past when the  table structure was changed.

单项选择题You are working in an online transaction processing （OLTP） environment. You realize that the salary for an employee， John， has been accidentally modified in the EMPLOYEES table. Two days ago， the data was in the correct state. Flashback logs generated during last two days are available in the flash recovery area.  Which option would you choose to bring the data to the correct state while ensuring that no other data in the same table is affected？（）

A.perform point-in-time recovery
B.perform a Flashback Table operation to restore the table to the state it was in two days ago
C.perform a Flashback Database operation to restore the database to the state it was in two days ago
D.perform Flashback Versions Query and Flashback Transaction Query to determine all the necessary undo SQL statements， and then use them for recovery

多项选择题ForwhichtwoSQLstatementscanyouusetheFlashbackTablefeaturetorevertatabletoitspreviousstate？（）

A.UPDATE TABLE
B.CREATE CLUSTER
C.TRUNCATE TABLE
D.ALTER TABLE MOVE
E.INSERT INTO···VALUES
F.ALTER TABLE···DROP COLUMN
G.ALTER TABLE···DROP PARTITION

单项选择题Why would you use the following FLASHBACK TABLE command？（）  FLASHBACK TABLE emp TO TIMESTAMP （’11：45’，’hh12：mi’）；

A.to undo the changes made to the EMP table since the specified time
B.to restore the EMP table that was wrongly dropped from the database
C.to view the transactions that have modified the EMP table since the specified time
D.to view the changes made to the EMP table for one or more rows since the specified time
E.to recover the EMP table to a point in time in the past by restoring the most recent backup

单项选择题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