ORA-12560: TNS:protocol adapter error(TNS:协议适配器...解决

这种问题一般是因为客户端不知道要连那个instance或者不知道要使用哪个TNS Alias

可能的原因1.服务没有起来

下边是Tom的一个Test Case来说明OracleServiceSID服务没有起来的话，是会引起ORA-12560错误的。

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C:\Documents and Settings\tkyte>sqlplus scott/tiger  
  
SQL*Plus: Release 10.1.0.4.0 - Production on Thu Sep 6 15:43:55 2007  
  
Copyright (c) 1982, 2005, Oracle.  All rights reserved.  
  
  
Connected to:  
Oracle Database 10g Enterprise Edition Release 10.1.0.4.0 - Production  
With the Partitioning, OLAP and Data Mining options  
  
scott%ORA10GR1> exit  
Disconnected from Oracle Database 10g Enterprise Edition Release 10.1.0.4.0 - Production  
With the Partitioning, OLAP and Data Mining options  
  
C:\Documents and Settings\tkyte>net stop oracleserviceora10gr1  
The OracleServiceORA10GR1 service is stopping.........  
The OracleServiceORA10GR1 service was stopped successfully.  
  
  
C:\Documents and Settings\tkyte>sqlplus scott/tiger  
  
SQL*Plus: Release 10.1.0.4.0 - Production on Thu Sep 6 15:44:35 2007  
  
Copyright (c) 1982, 2005, Oracle.  All rights reserved.  
  
ERROR:  
ORA-12560: TNS:protocol adapter error  
  
  
Enter user-name:  
ERROR:  
ORA-12560: TNS:protocol adapter error  
  
  
Enter user-name:  
ERROR:  
ORA-12560: TNS:protocol adapter error  
  
  
SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus  
  
C:\Documents and Settings\tkyte>net start oracleserviceora10gr1  
The OracleServiceORA10GR1 service is starting..........  
The OracleServiceORA10GR1 service was started successfully.  
  
  
C:\Documents and Settings\tkyte>sqlplus scott/tiger  
  
SQL*Plus: Release 10.1.0.4.0 - Production on Thu Sep 6 15:45:12 2007  
  
Copyright (c) 1982, 2005, Oracle.  All rights reserved.  
  
  
Connected to:  
Oracle Database 10g Enterprise Edition Release 10.1.0.4.0 - Production  
With the Partitioning, OLAP and Data Mining options  
  
scott%ORA10GR1><A name=PAGETOP></A> 

C:\Documents and Settings\tkyte>sqlplus scott/tiger

SQL*Plus: Release 10.1.0.4.0 - Production on Thu Sep 6 15:43:55 2007

Copyright (c) 1982, 2005, Oracle.  All rights reserved.


Connected to:
Oracle Database 10g Enterprise Edition Release 10.1.0.4.0 - Production
With the Partitioning, OLAP and Data Mining options

scott%ORA10GR1> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.1.0.4.0 - Production
With the Partitioning, OLAP and Data Mining options

C:\Documents and Settings\tkyte>net stop oracleserviceora10gr1
The OracleServiceORA10GR1 service is stopping.........
The OracleServiceORA10GR1 service was stopped successfully.


C:\Documents and Settings\tkyte>sqlplus scott/tiger

SQL*Plus: Release 10.1.0.4.0 - Production on Thu Sep 6 15:44:35 2007

Copyright (c) 1982, 2005, Oracle.  All rights reserved.

ERROR:
ORA-12560: TNS:protocol adapter error


Enter user-name:
ERROR:
ORA-12560: TNS:protocol adapter error


Enter user-name:
ERROR:
ORA-12560: TNS:protocol adapter error


SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus

C:\Documents and Settings\tkyte>net start oracleserviceora10gr1
The OracleServiceORA10GR1 service is starting..........
The OracleServiceORA10GR1 service was started successfully.


C:\Documents and Settings\tkyte>sqlplus scott/tiger

SQL*Plus: Release 10.1.0.4.0 - Production on Thu Sep 6 15:45:12 2007

Copyright (c) 1982, 2005, Oracle.  All rights reserved.


Connected to:
Oracle Database 10g Enterprise Edition Release 10.1.0.4.0 - Production
With the Partitioning, OLAP and Data Mining options

scott%ORA10GR1>修改方法：控制面板>管理工具>服务里边把OracleServiceSID起起来

可能的原因2.ORACLE_SID环境变量没有指定（最常见引起ORA-12560问题的原因）

检查方法，命令行(cmd)下，

C:\Documents and Settings\ptian>set oracle_sid

ORACLE_SID=test

ORACLE_SID是sqlplus默认连接的数据库instance,即sqlplus user/pwd连接的instance，如果不指定sqlplus里连接的时候就需要明确@你的instance,eg,sqlplus user/pwd@instance .

修改方法：在注册表中，HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\KEY_OraDb10g_home1\ORACLE_SID 需指向你的Instance(eg.orcl)；或者在系统的环境变量里加ORACLE_SID项，值为Instance的SID。

可能的原因3.TNS_ADMIN环境变量没有指定

检查方法，命令行(cmd)下，

C:\Documents and Settings\ptian>set TNS_ADMIN

TNS_ADMIN=D:\oracle\product\10.1.0\Db_1\NETWORK\ADMIN

TNS_ADMIN应该返回你的tnsnames.ora所在的目录

修改方法：可以在注册表HKEY_LOCAL_MACHINE\SOFTWARE\ORACLE\HOME0\TNS_ADMIN或者环境变量中指定。

可能的原因4.ORACLE_HOME环境变量没有指定

和上边的方法类似，检查Oracle_Home环境变量

可能的原因5.tnsnames.ora文件内容不对

A sample:

TEST =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = ptian-cn.cn.oracle.com)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = test)
    )
  )