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

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？（）

单项选择题 On Monday， you dropped the DEPT table from your schema and then you re-created the DEPT table in your schema. On Wednesday， you have a requirement to restore the DEPT table from the recycle bin.  Which statement is correct？（）