【Oracle】-【权限-ORA-04043】- ORA-04043: object "SYS"."V_$DATABASE" does not exist解决
用非dba账号(但赋予了DBA角色)登录一个新的10g数据库想看下版本号，
SQL> desc v$instance;
ERROR:
ORA-04043: object "SYS"."V_$INSTANCE" does not exist
奇怪，之前有个9i的库，同样的账号就可以查看呢？？？
分析：
这里显示的是"SYS"."V_$INSTANCE"对象不存在，我们知道，当账户没有某个对象的权限时，查询该对象，可能返回的就是对象不存在的错误(我觉得有时还是有点歧义，或者说有点误导的)。如下是04043的说明，也没有提到是因为无权限的原因。
ORA-04043: object string does not exist
Cause: An object name was specified that was not recognized by the system. There are several possible causes:
- An invalid name for a table, view, sequence, procedure, function, package, or package body was entered. Since the system could not recognize the invalid name, it responded with the message that the named object does not exist.
- An attempt was made to rename an index or a cluster, or some other object that cannot be renamed.
Action: Check the spelling of the named object and rerun the code. (Valid names of tables, views, functions, etc. can be listed by querying the data dictionary.)
那好，说这个"SYS"."V_$INSTANCE"不存在，就登录sys，
SQL> desc V$INSTANCE
Name Null? Type
----------------------------------------- -------- ----------------------------
INSTANCE_NUMBER NUMBER
INSTANCE_NAME VARCHAR2(16)
HOST_NAME VARCHAR2(64)
VERSION VARCHAR2(17)
STARTUP_TIME DATE
STATUS VARCHAR2(12)
PARALLEL VARCHAR2(3)
THREAD# NUMBER
ARCHIVER VARCHAR2(7)
LOG_SWITCH_WAIT VARCHAR2(15)
LOGINS VARCHAR2(10)
SHUTDOWN_PENDING VARCHAR2(3)
DATABASE_STATUS VARCHAR2(17)
INSTANCE_ROLE VARCHAR2(18)
ACTIVE_STATE VARCHAR2(9)
BLOCKED VARCHAR2(3)
说明这个对象是存在的，只是现在只能通过这个SYS账户才能查询。
再从V$INSTANCE查询出错的原因分析，这个V$是视图，它提示的是V_$INSTANCE找不到，说明V$INSTANCE是对V_$INSTANCE的封装。
赋予dcsopen查询v$instance的权限：
SQL> GRANT SELECT ON v$instanceTO dcsopen;
GRANT SELECT ON v$instance TO dcsopen
*
ERROR at line 1:
ORA-02030: can only select from fixed tables/views
不让赋予它的查询权限？
是否V$INSTANCE还有其它的对象？除了这个同义词。
SQL> SELECT owner, object_type FROM dba_objects WHERE object_name = 'V$INSTANCE';
OWNER OBJECT_TYPE
------------------------------ -------------------
PUBLIC SYNONYM
除了同义词外，应该是没有其它的同名对象了。
再尝试：
SQL> CREATE PUBLIC SYNONYM P_INSTANCE for V$INSTANCE;
Synonym created.
SQL> grant select on p_instance to dcsopen;
grant select on p_instance to dcsopen
*
ERROR at line 1:
ORA-02030: can only select from fixed tables/views
仍旧不允许赋予查询v$instance的权限。
以前对于同义词的理解中，如果账户没有访问同义词对应基表的访问权限，查询同义词就会提示找不到对象的报错。
SQL> create public synonym p_instance for v$instance;
Synonym created.
SQL> grant select on p_instance to dcsopen;
grant select on p_instance to dcsopen
*
ERROR at line 1:
ORA-02030: can only select from fixed tables/views
也是不允许。
这里提示的fixed tables/views，表明可能与Dynamic Performance Views有关，因为DPV是基于fixed tables的。这些表是Oracle底层C结构体的精髓表现。
那我们看下上面提到的V_$INSTANCE，
SQL> set long 5000
SQL> SELECT text
2 FROM dba_views
3 WHERE owner = 'SYS'
4 AND view_name = 'V_$INSTANCE';
TEXT
--------------------------------------------------------------------------------
select "INSTANCE_NUMBER","INSTANCE_NAME","HOST_NAME","VERSION","STARTUP_TIME","S
TATUS","PARALLEL","THREAD#","ARCHIVER","LOG_SWITCH_WAIT","LOGINS","SHUTDOWN_PEND
ING","DATABASE_STATUS","INSTANCE_ROLE","ACTIVE_STATE","BLOCKED" from v$instance
郁闷了，怎么又调用回来了？v$instance。
有帖子建议别查询传统意义的视图字典了，查询v$fixed_view
