Which pseudocolumn could you use to identify a unique row in a Flashback Versions Query？（）

单项选择题WhichofthefollowingstatementsbestdescribesFlashbackVersionsQuery？（）

A. Flashback Versions Query is used to make changes to multiple versions of data that existed between two points in time.
B. Flashback Versions Query is used to view all version changes on rows that existed between the time  the query was executed and a point in time in the past.
C. Flashback Versions Query is used to view version changes and the SQL to undo those changes on rows that existed between two points in time.
D. Flashback Versions Query is used to view all version changes on rows that existed between two  points in time.

多项选择题Users notify you that their application is failing every time they try to add new records. Because of poor application design， the actual ORA error message is unavailable.  What might be the problem？（）

A. The application user has exceeded their undo quota.
B. The FLASHBACK GUARANTEE option is set on the undo tablespace.
C. The table is currently being queried by a Flashback Transaction Query operation.
D. The table is currently being queried by a Flashback Versions Query operation.
E. The RETENTION GUARANTEE option is set on the undo tablespace.

多项选择题InordertoperformFlashbackTransactionQueryoperations，whichofthesestepsarerequired？（）

A. Ensure that database is running with version 10.1 compatibility.
B. Enable Flashback Logging.
C. Enable Supplemental Logging.
D. Ensure that the database is running with version 10.0 compatibility.
E. Ensure that the database is in ARCHIVELOG mode.

单项选择题AUM has been retaining about 15 minutes worth of undo. You want to double the retentionperiod， but not at the expense of new transactions failing. You decide to alter the system to set the parameter UNDO_RETENTION=18000. However， AUM still retains only about 15 minutes worth of undo.  What is the problem？ （）

A. You need to alter the undo tablespace to add the RETENTION GUARANTEE setting.
B. You need to increase the size of the undo tablespace.
C. The undo tablespace is not set to auto-extend.
D. You need to alter the Recycle Bin to add the RETENTION GUARANTEE setting.

单项选择题A user named Arren is executing this query：   select table_name，operation，undo_sql  from  flashback_transaction_query t，  （select versions_xid as xid  from employees versions between scn minvalue and maxvalue  where employee_id = 123） e  where t.xid = e.xid；   When the query runs，he receives an ORA-01031： insufficient privileges error. Since the user owns the employees table，you know that it is not the problem.  Which of the following SQL statements will correct this problem？（）

A. GRANT SELECT ANY TRANSACTION TO ARREN
B. GRANT SELECT ON FLASHBACK_TRANSACTION_QUERY TO ARREN
C. GRANT SELECT_ANY_TRANSACTION TO ARREN
D. GRANT FLASHBACK TO ARREN
E. GRANT SELECT ANY VIEW TO ARREN