OCP-1Z0-053-V12.02-85题

85.You executed the following command to drop a user:

DROP USER scott CASCADE;

Which two statements regarding the above command are correct? (Choose two.)

A. All the objects of scott are moved to the Recycle Bin.

B. Any objects in the Recycle Bin belonging to scott are purged.

C. All the objects owned by scott are permanently dropped from the database.

D. All the objects of scott in the Recycle Bin must be purged before executing the DROP command.

E. Any objects in the Recycle Bin belonging to scott will not be affected by the above DROP command.

Answer: BC

答案解析：

参考：http://docs.oracle.com/cd/E11882_01/server.112/e41084/statements_9008.htm#SQLRF54974

ACD描述错误，题要求选两个，故选BC

DROP USER

Purpose

Use the DROP USER statement to remove a database user and optionally remove the user's objects.

In an Oracle Automatic Storage Management (Oracle ASM) cluster, a user authenticated AS SYSASM can use this clause to remove a user from the password file that is local to the Oracle ASM instance of the current node.

When you drop a user, Oracle Database also purges all of that user's schema objects from the recycle bin.

Prerequisites

You must have the DROP USER system privilege. In an Oracle ASM cluster, you must be authenticated AS SYSASM.

user

Specify the user to be dropped. Oracle Database does not drop users whose schemas contain objects unless you specify CASCADE or unless you first explicitly drop the user's objects.

Restriction on Dropping Users 

You cannot drop a user whose schema contains a table that uses a flashback data archive for historical tracking. You must first disable the table's use of the flashback data archive.

CASCADE

Specify CASCADE to drop all objects in the user's schema before dropping the user. You must specify this clause to drop a user whose schema contains any objects.

• If the user's schema contains tables, then Oracle Database drops the tables and automatically drops any referential integrity constraints on tables in other schemas that refer to primary and unique keys on these tables.

• If this clause results in tables being dropped, then the database also drops all domain indexes created on columns of those tables and invokes appropriate drop routines.