生产库上要修改生产用户的密码，密码修改完后就涉及到修改dblink的密码。
11gR2版本之前只能删除dblink后重建，11gR2版本后可以直接修改。
修改dblink的密码有两种方法：
1、删除dblink后重建
2、直接修改dblink的用户密码
下面测试两种方法：
测试库版本：11.2.0.4.0
创建两个dblink，一个PUBLIC另一个PRIVATE
create PUBLIC database link link_101 connect to SYSTEM identified by "123456" using '(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.56.11)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = mydb)
)
)';
create database link link_102 connect to SYSTEM identified by "123456" using '(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.56.11)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = mydb)
)
)';
sys@ORCL>select * from dual@link_101;
DUM
---
X
sys@ORCL>select * from dual@link_102;
DUM
---
X修改远端数据库密码
SQL> alter user system identified by "654321";
User altered.
sys@ORCL>select * from dual@link_101;
select * from dual@link_101
*
ERROR at line 1:
ORA-01017: invalid username/password; logon denied
ORA-02063: preceding line from LINK_101
sys@ORCL>select * from dual@link_102;
select * from dual@link_102
*
ERROR at line 1:
ORA-01017: invalid username/password; logon denied
ORA-02063: preceding line from LINK_102方法一：
sys@ORCL>drop public database link link_101;
Database link dropped.
sys@ORCL>drop database link link_102;
Database link dropped.
create PUBLIC database link link_101 connect to SYSTEM identified by "654321" using '(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.56.11)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = mydb)
)
)';
create database link link_102 connect to SYSTEM identified by "654321" using '(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.56.11)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = mydb)
)
)';
sys@ORCL>select * from dual@link_101;
DUM
---
X
sys@ORCL>select * from dual@link_102;
DUM
---
X方法二：
sys@ORCL>select * from dual@link_101;
select * from dual@link_101
*
ERROR at line 1:
ORA-01017: invalid username/password; logon denied
ORA-02063: preceding line from LINK_101
sys@ORCL>select * from dual@link_102;
select * from dual@link_102
*
ERROR at line 1:
ORA-01017: invalid username/password; logon denied
ORA-02063: preceding line from LINK_102
sys@ORCL>alter public database link link_101 connect to system identified by "654321";
Database link altered.
sys@ORCL>alter database link link_102 connect to system identified by "654321";
Database link altered.
sys@ORCL>select * from dual@link_101;
DUM
---
X
sys@ORCL>select * from dual@link_102;
DUM
---
X方法二如果提示ORA-01031: insufficient privileges，则赋权grant alter database link to zx;
