【Oracle 12c】CUUG OCP认证071考试原题解析（32）

View the Exhibit and examine the data in EMP and DEPT tables.

In the DEPT table, DEPTNO is the PRIMARY KEY.

In the EMP table, EMPNO is the PRIMARY KEY and DEPTNO is the FOREIGN KEY referencing

the DEPTNO column in the DEPT table.

What would be the outcome of the following statements executed in the given sequence?

DROP TABLE emp;

FLASHBACK TABLE emp TO BEFORE DROP;

INSERT INTO emp VALUES (2,‘SCOTT‘, 10);

INSERT INTO emp VALUES (3,‘KING‘, 55);

A) Both the INSERT statements would succeed because none of the constraints on the table are automatically retrieved when the table is flashed back.

B) Only the second INSERT statement would succeed because all the constraints except referential integrity constraints that reference other tables are retrieved automatically after the table is flashed back.

C) Both the INSERT statements would fail because all constraints are automatically retrieved when the table is flashed back.

D) Only the first INSERT statement would succeed because all the constraints except the primary key constraint are automatically retrieved after a table is flashed back.

Answer：B

(解析：除了引用其他表的引用完整性约束之外，所有约束在表被闪回之后自动恢复，已经做过实验)

原文：https://blog.51cto.com/13854012/2353411