ANBOB™

ocp证书有没有用，虽然现在water ocp许多，但是有很多单位还是认这个证，很纠结，昨晚看题库，发现两个错误的，所以提醒想考证的现在网上题库的答案不一定是正确的

225,
One of the database users accidentally deleted all the rows of a critical table and committed the delete at 1:30 p.m. You senior database administrator，asks you to retrieve the lost data.
Which two actions would you use to ensure that there is no impact on other connected users while retrieving the deleted rows? Choose two.
A> Use a flashback query to retrieve the rows that were deleted
B> Use convential incremental export and then import the affected object
C> Shutdown the database in NORMAL mode and restart the database instance
D> Use DBMS_META package to reconstruct the object using undo segments
E> Use Tablespace Point in Time Recovery (TSPITR) method to recover the table and the data
F> Use Oracle Data Pump with flashback_time option to en table flashback export and then import the affected object.

题库答案 BE

意思是当一个用户误删了表里的全部数据，如何在不影响其它连接的情况下找回数据，我认为主要是不影响其它连接考点关键字，
a,闪回查询，我觉的如果不考虑undo被覆盖可以闪回查询以前的数据再insert进原表
b,exp 增量导出 9i以后已废弃，但有时提示其它也启作用，问题是数据已经没了不可行
c,重启恢复，不可能
d,利用undo重建对象，不可行
e,基于时间点的表空间恢复，那样影响表空间其它表也就有可能影响其它用户
F,数据泵用闪回时间导出再导入，这个也是可行的
所以应该是A,F

180. QUESTION 14
You work as a database administrator，Your database is configured for automatic undo management. UNDO_RETENTION is set to 3 hours.
You want to flashback a table that was created last year.
How far back can the flashback query go?
A> 3 hours
B> 6 months
C> until last year
D> until last commit
E> until the point when the undo tablespace was refreshed
F> until the database is shutdown and the memory erased

题库答案A

意思是UNDO_RETENTION设定了3小时，最多能闪回去年建立的一个表的多少时间？
无论是哪年建年份肯定无关，3小时呢？如果表空间未指定UNDO_RETENTION，无法保证3小时的，还有表空间大小的限制，因为undo是循环使用的，如果一个小时内undo就被覆盖，那3小时也是无法闪回，如果设时间为1秒，但你的1小时前undo表空间没被覆盖，那一小时也是可以闪回的
所以这个应该选E

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