OCP-1Z0-053-V12.02-373题

 

373.Which of the following Oracle features utilize the undo tablespace? (Choose all that apply)

A. Flashback Query

B. Flashback Drop

C. Flashback Table

D. Flashback Database

E. Transaction Processing

F. Recycle Bin

Answer: ACE

答案解析：

Transaction Processing事务处理会在undo和redo产生数据。

• flashback drop：利用recyelebin 回收站原理
• flashback table TEST10 to before drop [rename to test11];可以重命名 

• flashback query ，依赖undo数据，先查询，在做insert
• insert into test10 select * from test10 as of timestamp to_timestamp('2013-09-23 11:52:06','yyyy-mm-dd hh24:mi:ss'); 

• flashback table 依赖undo块
• flashback table scott.test10 to scn 1952615
• insert into test10 select * from scott.test10 as of scn 1952615;        

• flashback database DDL语句，依赖闪回区的闪回日志
• flashback database to timestamp to_timestamp('2013-09-23 15:09:52','yyyy-mm-dd hh24:mi:ss');时间减一秒。