Oracle OCP 1Z0-053 Q686(Flashback Table)

686. You execute the following FLASHBACK TABLE command:

Which two statements are correct?(Choose two.)
A.The EMP table that was dropped by mistake earlier is restored.
B.The FLASHBACK TABLE statement is executed as a single transaction.
C.The FLASHBACK TABLE statement does not maintain existing indexes on the EMP table.
D.The changes made to the EMP table since the specified time are undone if no constraint is violated
during flashback.
Answer:BD

答案A是錯誤的，驗證如下：

SQL> create table t1 as select rownum rn from dual connect by rownum <= 10000;


Table created.


SQL> select sysdate from dual;


SYSDATE
---------
24-MAR-16


SQL> select to_char(sysdate, 'yyyymmdd hh24:mi:ss') from dual;


TO_CHAR(SYSDATE,'
-----------------
20160324 11:16:57


SQL> drop table t1;


Table dropped.


SQL> flashback table t1 to timestamp to_timestamp('20160324 11:16:57','yyyymmdd hh24:mi:ss');
flashback table t1 to timestamp to_timestamp('20160324 11:16:57','yyyymmdd hh24:mi:ss')
                *
ERROR at line 1:
ORA-00942: table or view does not exist




SQL> flashback table t1 to before drop;


Flashback complete.


SQL> select count(*) from t1;


  COUNT(*)
----------
     10000

參考：http://blog.csdn.net/rlhua/article/details/17417859

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