18、Evaluate the following ALTER TABLEstatement:
ALTER TABLE orders SET UNUSED (order_date);
Which statement is true?
A. After executing the ALTER TABLEcommand, you can add a new column called ORDER_DATE to the ORDERS table.
B. The ORDER_DATE column should be empty for the ALTER TABLE command to execute succsessfully.
C. ROLLBACK can be used to get back the ORDER_DATE column in the ORDERStable.
D. The DESCRIBE command would still display the ORDER_DATE column.
Source ： cuug
来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/70010796/viewspace-2853453/ ，如需转载，请注明出处，否则将追究法律责任。
请登录后发表评论
登录
全部评论
最新文章
- 从小白到专家 PG技术大讲堂 - Part 2：PG源代码安装
- 从小白到专家 PG 技术大讲堂 - Part 1：PG 简介
- ocp 19c考题，科目082考试题(34)
- ocp 19c考题，科目082考试题(33)
- ocp 19c考题，科目082考试题(32) -
- ocp 19c考题，科目082考试题(31) - resource_limit
- ocp 19c考题，科目082考试题(30) - default profile
- ocp 19c考题，科目082考试题(29) - about profiles
- ocp 19c考题，科目082考试题(28) - oracle profiles
- ocp 19c考题，科目082考试题(27) - order by clause
