上次的操作中，修改了登录密码，只可惜dbsnmp这个用户不是admin，好多操作做不了（下次一定要看清楚了再改-_-），下面介绍下在system无法登录时，怎么修改密码。
在CMD中启用SQLPLUS，用conn / as sysdba 登录
连接到:
Oracle Database 10g Express Edition Release 10.2.0.1.0 – Production
SQL> connect sys/oracle as sysdba
已连接。
SQL> select username,password from dba_users;
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
SYS
93A0727B64A4926C
SYSTEM
E049D4E52B9218ED
ANONYMOUS
anonymous
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
DBSNMP
E066D214D5421CCC
MDSYS
72979A94BAD2AF80
OUTLN
4A3BA55E08595C81
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
DIP
CE4A36B8E06CA59C
TSMSYS
3DF26A8B17D0F29F
FLOWS_FILES
364B78B9EABB9E56
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
CTXSYS
D1D21CA56994CAB6
FLOWS_020100
16E4C012E98710D0
XDB
E76A6BD999EF9FF1
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
HR
4C6D73C3E8B0F0DA
已选择13行。
SQL> connect system/oracle
ERROR:
ORA-01017: invalid username/password; logon denied
警告: 您不再连接到 ORACLE。
SQL> connect sys/oracle as sysdba
已连接。
SQL> alter user system identified by manager;
用户已更改。
SQL> select username,password from dba_users;
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
SYS
93A0727B64A4926C
SYSTEM
D4DF7931AB130E37
ANONYMOUS
anonymous
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
DBSNMP
E066D214D5421CCC
MDSYS
72979A94BAD2AF80
OUTLN
4A3BA55E08595C81
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
DIP
CE4A36B8E06CA59C
TSMSYS
3DF26A8B17D0F29F
FLOWS_FILES
364B78B9EABB9E56
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
CTXSYS
D1D21CA56994CAB6
FLOWS_020100
16E4C012E98710D0
XDB
E76A6BD999EF9FF1
USERNAME
------------------------------------------------------------
PASSWORD
------------------------------------------------------------
HR
4C6D73C3E8B0F0DA
已选择13行。
SQL> connect system/manager
已连接。
SQL> connect sys/oracle as sysdba
已连接。
SQL> alter user system identified by values 'D4DF7931AB130E37';
用户已更改。
SQL> connect system/oracle
ERROR:
ORA-01017: invalid username/password; logon denied
警告: 您不再连接到 ORACLE。
SQL> connect sys/oracle as sysdba
已连接。
SQL> connect system/manager
已连接。
到此已连接成功，可以做其他操作了
SQL> connect dbsnmp/dbsnmp
已连接。