原题：
You execute the commands:
SQL>CREATE USER sidney
IDENTIFIED BY out_standing1
DEFAULT TABLESPACE users
QUOTA 10M ON users
TEMPORARY TABLESPACE temp
ACCOUNT UNLOCK;
SQL> GRANT CREATE SESSION To sidney;
Which two statements are true?
A) The user SIDNEY is created and authenticated by the operating system.
B) The user SIDNEY can connect to the database instance but requires relevant privileges to create objects in the USERS tablespace.
C) The user SIDNEY is created but cannot connect to the database instance because no profile
is assigned to the user.
D) The CREATE USER command fails if any role with the name SIDNEY exists In the database.
E) The user SIDNEY can connect to the database instance but cannot perform sort operations because no space quota Is specified for the TEMP tablespace.
经过验证：
答案为BD
验证过程：
1.创建pdb
CREATE PLUGGABLE DATABASE pdb1 ADMIN USER admin1 identified by admin1 roles = (dba) DEFAULT TABLESPACE users datafile ‘+DATA/ORCL/pdb1/pdb101.dbf‘ SIZE 250M AUTOEXTEND ON FILE_NAME_CONVERT = (‘+DATA/ORCL/pdbseed/‘,‘+DATA/ORCL/pdb1/‘) STORAGE (MAXSIZE 2G) PATH_PREFIX = ‘+DATA/ORCL/PDB1‘;
2.连接pdb
alter session set container=pdb1;
alter database open;
3.创建用户测试B选项
CREATE USER sidney IDENTIFIED BY out_standing1 DEFAULT TABLESPACE users QUOTA 10M ON users TEMPORARY TABLESPACE temp ACCOUNT UNLOCK;
GRANT CREATE SESSION To sidney;
SQL> create table test1 (id int) tablespace users;
create table test1 (id int) tablespace users
*
ERROR at line 1:
ORA-01031: insufficient privileges
4.创建role测试D选项
SQL> drop user sidney cascade;
User dropped.
SQL> create role sidney not identified;
Role created.
SQL> CREATE USER sidney IDENTIFIED BY out_standing1 DEFAULT TABLESPACE users QUOTA 10M ON users TEMPORARY TABLESPACE temp ACCOUNT UNLOCK;
CREATE USER sidney IDENTIFIED BY out_standing1 DEFAULT TABLESPACE users QUOTA 10M ON users TEMPORARY TABLESPACE temp ACCOUNT UNLOCK
*
ERROR at line 1:
ORA-01920: user name ‘SIDNEY‘ conflicts with another user or role name
原文：https://www.cnblogs.com/liang-ning/p/12963927.html