【2019年8月版本】OCP 071认证考试最新版本的考试原题-第12题

时间 2019-11-08

标签 2019年8月版本 ocp 认证考试最新版本繁體版

原文原文链接

Choone twoide

Which three statements are true about dropping and unused columns in an Oracle database?spa

A) A primary key column referenced by another column as a foreign key can be dropped if using the CASCADE option.three

B) A DROP COLUMN command can be rolled backit

C) An UNUSED column's space is redaimed automatially when the block containing that column is next queriedio

D) An UNUSED column's space is redaimed automatially when the row containing that column is next queried.table

E) Partition key columns cannot be dropped.class

F) A column that is set to NNUSED still counts towards the limit of 1000 columns per table.sed

Answer：AEcommand

(解析：im

删除主键列时能够加 cascade 选项，同时把主外键约束一块儿删除。

ORA-12984: 没法删除分区列，E 对;