You want to use the Flashback Transaction Query feature to identify all the changes made to your database within a specific time period. What is a prerequisite for using the Flashback Transaction Query feature？（）

单项选择题At 5：30 PM， a database administrator， William， is informed that an important record of employee no E0025 is missing from the SCOTT.EMPLOYEE table. At 4：30 P.M， the table contained the record of employee no E0025. William issues the following command to find the SQL statements that are used to undo the deletion：    SELECT operation， undo_sql， logon_user   FROM FLASHBACK_TRANSACTION_QUERY  WHERE xid=   HEXTORAW（’0100043E23456’）；   where ’0100043E23456’ is the transaction ID of the transaction that deleted the row. Before issuing the above statement， which task did William perform to identify the transaction ID of the transaction that deleted the row？（）

A. William used the Flashback Version Query feature.
B. William issued the CROSSCHECK command at the RMAN prompt.
C. William viewed the alert log file.
D. William used the Flashback Table feature.

单项选择题YouareemployedasaDBAinanorganization.YouareinformedthattherecordofEMP_NO1000ismissingfromtheSCOTT.EMPtable.Youarerequiredtoidentifytheuserwhodeletedtherecord，theSQLstatementthatwillundothedeletion，andthetransactionIDofthetransactionthatdeletedtheemployeerecord.Whichfeaturewillyouusetoperformthetasks？（）

A. Only the Flashback Table
B. Both the Flashback Transaction Query and the Flashback Version Query
C. Only the Flashback Drop
D. Only the Flashback Version

单项选择题InwhichscenariowillyouusetheFlashbackTransactionQueryfeature？（）

A. when you want to restore an important table that is dropped from the Recycle Bin
B. when you want to obtain the SQL statements to undo the deletion of some important records from a table by a transaction
C.when you want to restore a dropped user’s schema
D. when a row of a table is updated many times within a specific time period and you want all the versions of the row in the specified time period

单项选择题YouquerytheORDERStableanddiscoverthatordernumber1101ismissing.Oneofyourreports，generatedat5：00A.M.onApril23，2005usingOracleReports，includesthisordernumberintheoutput.Youhaveinserted100newordersintotheORDERStablesincegeneratingthisreport.Whichflashbacktechnologywouldyouusetorecoverordernumber1101intotheORDERStablewithoutlosingthe100ordersthatyouaddedafterthereportwasgenerated？（）

A. Flashback Table
B. Flashback Query
C.Flashback Version Query
D. Flashback Transaction Query

单项选择题YoudecidetoenableFlashbackDatabaseinyourOracle10gdatabasesothatfuturerecoverieswilltakelesstimethantraditionalrecoveries.WhichofthefollowingparametersmustbeincludedinyourinitializationparameterfilebeforeenablingFlashbackDatabase？（）

A. DB_RECOVERY_FILE_DEST only
B. DB_FLASHBACK_RETENTION_TARGET only
C. DB_RECOVERY_FILE_DEST_SIZE and DB_RECOVERY_FILE_DEST only
D. DB_RECOVERY_FILE_DEST and DB_FLASHBACK_RETENTION_TARGET only
E. DB_RECOVERY_FILE_DEST_SIZE， DB_RECOVERY_FILE_DEST and
F. DB_FLASHBACK_RETENTION_TARGET