1.使用SYSDBA身份连接到数据库

sqlplus /nolog
conn / as sysdba;

2.创建用户账户USERA，其口令为orcl，默认表空间为USERS，临时表空间为TEMP，对表空间的配额限制为10MB

create user usera identified by orcl
default tablespace users
temporary tablespace temp
quota 10M on users;

3.向用户授予连接数据库系统的权限和角色RESOURCE权限

grant create session to usera;
grant resource to usera;

4.向用户授予对对象'SCOTT.EMP'的select,delete和update权限，并以用户USERA连接到数据库，查询SCOTT.EMP的表

grant select, delete, update on scott.emp to usera;
grant select, delete, update on usera;
conn usera/orcl;
select * form scott.emp;

5.撤销向用户USERA授予的系统权限，向用户授予CONNECT角色

conn / as sysdba;
revoke create session from usrea;
grant connect to usera;

6.创建一个角色ROLE1，授予其具有CREATE VIEW,CREATE PROCEDURE,CREATE TRIGGER的权限

create role role1;
grant create view, create procedure, create trigger to role1;

7.将创建的角色ROLE1授权给USERA

grant role1 to usera;

8.撤销USERA中的CREATE VIEW权限

revoke create view from role1;