对Oracle OCP 19c认证1Z0-083考试题库（第8题）的解析

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题目来源：http://blog.itpub.net/31544987/viewspace-2760495/

8、Examine the statements that use flashback technologies:

1. FLASHBACK TABLE customers TO TIMESTAMP TO_TIMESTAMP(‘2013-02-04 09:30:00’, ‘YYYY-MM-DD HH:MI:SS’);
2. SELECT * FROM customers AS OF SCN 123456;
3. FLASHBACK TABLE customers TO BEFORE DROP;
4. FLASHBACK DATABASE TO TIMESTAMP TO_TIMESTAMP(‘2013-02-04 09:30:00’, ‘YYYY-MM-DD HH:MI:SS’);
5. SELECT * FROM customers VERSIONS BETWEEN SCN 123456 AND 123999;
6. ALTER TABLE customers FLASHBACK ARCHIVE;
   Which set of statements depends on the availability of relevant undo data in the undo tablespace?
   A) 1,3,6
   B) 1,2,5
   C) 3,4,5
   D) 2,3,5,6

考的是flashback的相关概念，FLASHBACK ARCHIVE涉及专用的表空间，和undo无关，且6.的语法错误(缺一个参数)。所以A D排除。
C的相关性稍差一些
个人更倾向于B，更符合relevant(相关的 切题的)

仅供参考。

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