071考試不僅是OCP11g的考試科目，同時(shí)也是OCP 12c的考試科目，所以關(guān)心071考題的同學(xué)有很多，對(duì)此我們專門(mén)收集整理了近期071考試的原題，并對(duì)這些考題進(jìn)行講解，希望幫助廣大考生順利通過(guò)071考試。
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071考題解析-第57題、choose two:
Examine the structure of the DEPARTMENTS table
You execute the following command:
SQL> ALTER TABLE departments
SET UNUSED (country);
Which two statements are true?
A) A new column, COUNTRY, can be added to the DEPARTMENTS table after executing the command.
B) Indexes created on the COUNTRY column exist until the DROP UNUSED COLUMNS command is executed.
C) Unique key constraints defined on the COUNTRY column are removed.
D) Synonyms existing on the DEPARTMENTS table would have to be re-created.
E) Views created on the DEPARTMENTS table that include the COUNTRY column are automatically
modified and remain valid.
Answer：AC
(注意：列一旦被設(shè)置為 unused 以后，基于該列的約束、索引都被刪除，同時(shí)相關(guān)的視圖
被無(wú)法訪問(wèn)。經(jīng)過(guò)實(shí)驗(yàn)，可以馬上往該表添加名字一樣的列，有關(guān) set unsed 的知識(shí)點(diǎn)考題
前面也有出現(xiàn)過(guò)，本題一個(gè)特點(diǎn)就是答案 A)
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