053第383題，053383

053第383題，053383
383.At the request of a user, you issue the following command to restore a dropped table: flashback table
"BIN$F2JFfMq8Q5unbC0ceE9eJg==$0" to before drop; Later, the user notifies you that the data in the
table seems to be very old and out of date.
What might be the problem?
A. Because a proper range of SCNs was not specified, the wrong data was restored.
B. A proper range of timestamps was not specified, so the wrong data was restored.
C. A previous Flashback Drop operation had been performed, resulting in multiple versions of the table
being stored in the Recycle Bin.
D. Either option A or B could be correct. Not enough information was provided to determine which.
E. None of the above.
Answer: E

原題答案是E，有的版本答案選C，個人覺得正確答案是E

首先flashback drop 命令中沒有指定SCN或者TIMESTAMP的選項，所以ABD不對，然後FLASHBACK DROP命令不會在RECYCLE BIN裡面建立對象，所以C不對。

當處理資源回收筒裡面有多個相同original name的對象時，可以使用 對象在資源回收筒中的名字(unique name)，如題目中所示。本題目中最可能的原因是DBA對 recycle bin中的對象drop time 判斷錯誤，進而導致使用了錯誤的unique name.

You can also retrieve any table from the recycle bin, regardless of any collisions among original names, by using the unique recycle bin name of the table. For example, assume that you query the recycle bin as follows (sample output included):

SELECT object_name, original_name, createtime FROM   recyclebin;    OBJECT_NAME                    ORIGINAL_NAME   CREATETIME------------------------------ --------------- -------------------BIN$yrMKlZaLMhfgNAgAIMenRA==$0 TEMP_EMPLOYEES  2007-02-05:21:05:52BIN$yrMKlZaVMhfgNAgAIMenRA==$0 TEMP_EMPLOYEES  2007-02-05:21:25:13BIN$yrMKlZaQMhfgNAgAIMenRA==$0 TEMP_EMPLOYEES  2007-02-05:22:05:53

You can use the following command to retrieve the middle table:

FLASHBACK TABLE BIN$yrMKlZaVMhfgNAgAIMenRA==$0 TO BEFORE DROP;

參考：http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmflash.htm#BRADV81330

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