1.创建用户

create user zhu  identified by "123456";#刚创建的新用户权限为空，所以不能连接数据库
grant create session to zhu;#赋予create session才可以连接到数据库

2.修改用户的密码

SQL> conn zhu/123456;
Connected.
SQL> show user;
USER is "ZHU"
SQL> conn / as sysdba
Connected.
SQL> alter user zhu identified by zhuzhu;
User altered.
SQL> conn zhu/zhuzhu;
Connected.
SQL> show user
USER is "ZHU"

3.授权

SQL> grant  connect,resource  to  zhu;  #通过系统角色授权
Grant succeeded.
SQL> grant dba  to  zhu;                #授予用户dba权限
Grant succeeded.