select * from dba_users t where t.username='JEFF_CORE'

create user jeff_core identified by jeff_core;
grant dba to jeff_core;--授予DBA权限?
grant unlimited tablespace to jeff_core;--授予不限制的表空间?
grant select any table to jeff_core;--授予查询任何表?
grant select any dictionary to jeff_core;--授予 查询 任何字典

drop user "jeff_core" cascade

?

?

1.查看所有用户：
? select * from dba_users;
? select * from all_users;
? select * from user_users;

2.查看用户或角色系统权限( 直接赋值给用户或角色的系统权限 ) ：
? select * from dba_sys_privs;
? select * from user_sys_privs;

?

3.查看角色(只能查看登陆用户拥有的角色)所包含的权限

sql>select * from role_sys_privs;

4.查看用户对象权限：
? select * from dba_tab_privs;
? select * from all_tab_privs;
? select * from user_tab_privs;

5.查看所有角色：
? select * from dba_roles;

6.查看用户或角色所拥有的角色：
? select * from dba_role_privs;
? select * from user_role_privs;

?

7.查看哪些用户有sysdba或sysoper系统权限(查询时需要相应权限)

select * from V$PWFILE_USERS