看到群里有人问普通用户访问基表的问题，测试下如下：
X$基表可以通过创建视图，再对视图创建同义词方式、授权的方式来实现普通用户可以访问基表。
当然了普通用户访基表也是没道理的，理论上没必要，权限控制上也应该是不允许的。此处不考虑合理性，就此问题进行实验。
1.直接对X$基表创建同义词，其它用户无法实现访问。
SQL> show user
USER is “SYS”
SQL> select count(*) from sys.x$kcbwds;
COUNT(*)
———-
8
SQL> CREATE PUBLIC SYNONYM kcbwds FOR sys.x$kcbwds;
Synonym created.
SQL> grant select on sys.x$kcbwds to bys;
grant select on sys.x$kcbwds to bys
*
ERROR at line 1:
ORA-02030: can only select from fixed tables/views
———-
SQL> show user
USER is “BYS”
SQL> select count(*) from sys.x$kcbwds;
select count(*) from sys.x$kcbwds
*
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> select count(*) from kcbwds;
select count(*) from kcbwds
*
ERROR at line 1:
ORA-00942: table or view does not exist
————–
2.使用对X$基表创建视图的方法可以实现普通用户访问X$：
SQL> show user
USER is “SYS”
SQL> select count(*) from x$kcbwds;
COUNT(*)
———-
8
SQL> create view testa as select * from sys.x$kcbwds;
View created.
SQL> grant select on sys.testa to bys;
Grant succeeded.
SQL> conn bys/bys
Connected.
SQL> show user
USER is “BYS”
SQL> select count(*) from sys.testa;
COUNT(*)
———-
8
SQL> desc sys.testa
Name Null? Type
—————————————– ——– —————————-
ADDR RAW(4)
INDX NUMBER
INST_ID NUMBER
SET_ID NUMBER
POOL_ID NUMBER
DBWR_NUM NUMBER
BLK_SIZE NUMBER
后面省略。。。
3.可以通过对视图再加同义词方式来实现更简单的访问
SQL> CREATE PUBLIC SYNONYM testb FOR sys.testa;
Synonym created.
SQL> show user
USER is “SYS”
SQL> conn / as sysdba
Connected.
SQL> conn bys/bys
Connected.
SQL> select count(*) from testb;
COUNT(*)
———-
8
