Oracle设置sys用户以普通用户身份登录数据库

1、查看当前数据库版本及状态信息
SQL> select * from v$version;
BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
PL/SQL Release 11.2.0.4.0 - Production
CORE    11.2.0.4.0      Production
TNS for Linux: Version 11.2.0.4.0 - Production
NLSRTL Version 11.2.0.4.0 - Production

SQL> select dbid,name,open_mode from v$database;
      DBID NAME      OPEN_MODE
---------- --------- --------------------
1435632369 ORCL      READ WRITE


2、查看默认设置（sys必须以as sysdba权限登录时）
SQL> show user
USER is "SYS"
SQL> show parameter  O7_DICTIONARY_ACCESSIBILITY
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------

O7_DICTIONARY_ACCESSIBILITY          boolean     FALSE

SQL> conn sys/oracle

ERROR:
ORA-28009: connection as SYS should be as SYSDBA or SYSOPER

Warning: You are no longer connected to ORACLE.

SQL> conn sys/oracle as sysdba
Connected.


3、修改参数O7_DICTIONARY_ACCESSIBILITY=true，重启实例
SQL> alter system set O7_DICTIONARY_ACCESSIBILITY=true scope=spfile;
System altered.

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  413372416 bytes
Fixed Size                  2253784 bytes
Variable Size             327158824 bytes
Database Buffers           79691776 bytes
Redo Buffers                4268032 bytes
Database mounted.
Database opened.
SQL> show parameter  O7_DICTIONARY_ACCESSIBILITY
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
O7_DICTIONARY_ACCESSIBILITY          boolean     TRUE


4、此时sys可以以普通用户身份登录数据库
SQL> conn sys/oracle
Connected.
SQL> show user
USER is "SYS"


以普通用户身份登录数据库后，sys用户无启停数据库的权限
SQL> shutdown immediate
ORA-01031: insufficient privileges

SQL> startup force
ORA-01031: insufficient privileges
SQL> 


必须以as sysdba方式登录后才可以启停数据库
SQL> conn / as sysdba
Connected.
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  413372416 bytes
Fixed Size                  2253784 bytes
Variable Size             327158824 bytes
Database Buffers           79691776 bytes
Redo Buffers                4268032 bytes
Database mounted.
Database opened.


5、将参数O7_DICTIONARY_ACCESSIBILITY修改为默认值false
SQL> alter system set O7_DICTIONARY_ACCESSIBILITY=false  scope=spfile;
System altered.


SQL> startup force
ORACLE instance started.

Total System Global Area  413372416 bytes
Fixed Size                  2253784 bytes
Variable Size             327158824 bytes
Database Buffers           79691776 bytes
Redo Buffers                4268032 bytes
Database mounted.
Database opened.
SQL>