[每日一题] OCP1z0-047 :2013-08-02 权限―――分配系统权限


 

这题是考权限的知识点,权限分为两大类,系统权限和对象权限,这题主要讲系统权限,我们先来了解什么是系统权,什么是对象权限吧。

1、系统权限:允许用户在数据库中执行特定的操作

A、SYSDBA/SYSOPER这两个权限比较特殊

 

 

gyj@OCM> select * from dba_sys_privs where granteein('SYSDBA','SYSOPER');
 
no rows selected
 

 

 

B、DBA的系统权限是可以查到的

 

 

gyj@OCM> select * from dba_sys_privs where grantee='DBA';
 
GRANTEE                       PRIVILEGE                               ADM
---------------------------------------------------------------------- ---
DBA                            DROP ANY CUBE BUILD PROCESS              YES
DBA                           CREATE CUBE                             YES
DBA                           ALTER ANY CUBE DIMENSION                YES
DBA                           ALTER ANY MINING MODEL                   YES
 (中间结果省略)
…………………………..
202 rows selected.


 

 

C、普通用户的系统权限

 

 

 gyj@OCM> select * from  dba_sys_privs where grantee='GYJ';
 
GRANTEE                       PRIVILEGE                               ADM
------------------------------ -------------------------------------------
GYJ                           UNLIMITED TABLESPACE                    NO
 

 

 

D、 当前会话上的系统权限

 

 

gyj@OCM> select * from session_privs;
 
PRIVILEGE
----------------------------------------
ALTER SYSTEM
AUDIT SYSTEM
CREATE SESSION
ALTER SESSION
RESTRICTED SESSION
(中间结果省略)
……………………………
202 rows selected.

 

 

2、对象权限:允许用户访问和操纵特定的对象

   A、查对象权限    

 

 

gyj@OCM> select *  fromdba_tab_privs where grantee='GYJ';
 
no rows selected


 

 

B、查对象上列的权限

 

 

 gyj@OCM>select *  from dba_col_privs wheregrantee='GYJ';
 
no rows selected


 

 

 为什么没显示对象的权限和对象上列的权限呢,用户GYJ明明有对象的呀:

 

 

gyj@OCM> show user;
USER is "GYJ"
gyj@OCM> select table_name from tabs;
 
TABLE_NAME
------------------------------
T10


 

 

好,我登录到HR用户下给GYJ用户授对象权限

 

 

sys@OCM> conn hr/hr
Connected.
hr@OCM> grant select on employees to gyj;
 
Grant succeeded.
 
hr@OCM> grant update (department_id) onemployees to gyj;
 
Grant succeeded.


 

 

再次查对象权限就有结果了,这下明白这个意思了吧,好!这个就不多说了。

 

 

hr@OCM> select *  from dba_tab_privs wheregrantee='GYJ';
 
GRANTEE                        OWNER                          TABLE_NAME                     GRANTOR                 PRIVILEGE                                 GRA HIE
------------------------------------------------------------ ------------------------------------------------------------ ---------------------------------------- --- ---
GYJ                            HR                             EMPLOYEES                      HR                      SELECT                                    NO  NO
 
hr@OCM> select *  from dba_col_privs where grantee='GYJ';
 
GRANTEE                        OWNER                          TABLE_NAME                     COLUMN_NAME             GRANTOR                         PRIVILEGE                                GRA
------------------------------ ------------------------------------------------------------ ------------------------------------------------------------ ---------------------------------------- ---
GYJ                            HR                             EMPLOYEES                      DEPARTMENT_ID           HR                              UPDATE                                   NO
 

 

 

答案A:GRANT EXECUTE ON  proc1  TO PUBLIC;

grant 权限 on 数据库对象 to 用户是属于对象权限,而不是系统权限,所以答案不符合题意。

 

答案B:在create view后面不能加具体某个对象,没有这样的写法,操作如下直接报错

gyj@OCM> GRANT CREATE VIEW  ON T1TO hr;

GRANT CREATE VIEW  ON T1 TO hr

      *

ERROR at line 1:

ORA-00990: missing or invalid privilege

 

分配创建视图的系统权限应该这样写

gyj@OCM> GRANT CREATE VIEW   TOhr;

 

Grant succeeded.

 

gyj@OCM> GRANT CREATE ANY VIEW TO HR;

 

Grant succeeded.

 

查整个库关于CREATE VIEW的系统权限,如下:


 

答案D:没有ALL这个用户

gyj@OCM> GRANT CREATE SESSION TO ALL;

GRANT CREATE SESSION TO ALL

                        *

ERROR at line 1:

ORA-00987: missing or invalid username(s)

 

应该具体某个用户,比如给hr用户授予连接的权限

gyj@OCM> GRANT CREATE SESSION TO HR;

 

Grant succeeded.

 

 

正确答案:C

 

总结:这里要搞清楚系统权限和对象权限,系统权限的视图:dba_sys_privs

 


posted on 2013-08-02 23:03  you Richer  阅读(216)  评论(0编辑  收藏  举报