ORA-12317: logon to database (link name string) denied
Cause: There are several possible causes for this error. First, you can get this error if your username (and password, if you are using database instead of operating system authentication) in the secondary database are not identical to your username (and password) in the primary database. Second, you can get this error if your username in the secondary database is invalid (has not been created). Third, you can get this error if the username/password combination specified in the connect string of the database link definition is invalid (either not created or has an invalid password).
Action: In the first case, ensure that the secondary database contains a username (and password, if you are using database authentication) identical to the one you are using in the primary database. In general, you should always use operating system authentication in Trusted ORACLE (see the Trusted ORACLE RDBMS Guide to Security Features for more information about the advantages of OS authentication). In the second case, ensure that your username in the secondary database has been created. In the third case, ensure that the username specified in the connect string has been created in the secondary database.
Oracle 错误ORA-12317表明数据库链接（链接名字字符串）被拒绝登陆。
1. 您的连接字符串不正确，比如您的连接字符串可能没有所有可用的连接参数，或者存在格式错误。
2. 您提供的连接字符串不受服务器支持。由于不同版本的数据库实例可能包含不同的参数，连接字符串必须十分精确，作为一个实例的连接字符串可能不适用于另一个类型的实例。
1. 检查链接字符串是否正确。检查参数是否都是正确的格式，且值正确。
2. 确认服务器是否支持提供的链接字符串。
3. 检查用户名和密码是否正确。