sql - ORA-12154 : TNS:could not resolve the connect identifier specified on a table

Question

我在访问外部数据库中的一个表时遇到了 TNS 错误。但是当我尝试通过相同的外部数据库链接访问其他表时，它没有任何错误。

可能是什么原因造成的？

SELECT *
FROM tablename@db;

错误:

12154. 00000 -  "TNS:could not resolve the connect identifier specified"
*Cause:    A connection to a database or other service was requested using
           a connect identifier, and the connect identifier specified could not
           be resolved into a connect descriptor using one of the naming methods
           configured. For example, if the type of connect identifier used was a
           net service name then the net service name could not be found in a
           naming method repository, or the repository could not be
           located or reached.
*Action:   
           - If you are using local naming (TNSNAMES.ORA file):
           - Make sure that "TNSNAMES" is listed as one of the values of the
           NAMES.DIRECTORY_PATH parameter in the Oracle Net profile
           (SQLNET.ORA)
           - Verify that a TNSNAMES.ORA file exists and is in the proper
           directory and is accessible.
           - Check that the net service name used as the connect identifier
           exists in the TNSNAMES.ORA file.
           - Make sure there are no syntax errors anywhere in the TNSNAMES.ORA
           file.  Look for unmatched parentheses or stray characters. Errors
           in a TNSNAMES.ORA file may make it unusable.
           - If you are using directory naming:
           - Verify that "LDAP" is listed as one of the values of the
           NAMES.DIRETORY_PATH parameter in the Oracle Net profile
           (SQLNET.ORA).
           - Verify that the LDAP directory server is up and that it is
           accessible.
           - Verify that the net service name or database name used as the
           connect identifier is configured in the directory.
           - Verify that the default context being used is correct by
           specifying a fully qualified net service name or a full LDAP DN
           as the connect identifier
           - If you are using easy connect naming:
           - Verify that "EZCONNECT" is listed as one of the values of the
           NAMES.DIRETORY_PATH parameter in the Oracle Net profile
           (SQLNET.ORA).
           - Make sure the host, port and service name specified
           are correct.
           - Try enclosing the connect identifier in quote marks.
Error at Line: 2 Column: 6

Answer 1

首先从您的 Oracle 实例所在的主机尝试 tnsping 在您的 db_link 配置中使用的 oracle 实例。

tnsping SID/TNS Alias

如果你得到类似的东西

TNS-03505: Failed to resolve name

你需要检查你的 tnsnames.ora 文件，看看你是否有一个 tns 别名指向 tablename@db 所在的数据库实例。

• 如果没有条目添加一个并再次测试。

• 还要确保不需要域，为此您需要验证/检查位于 TNS_ADMIN 位置的 sqlnet.ora。

• 另一件事，如果你在 Windows 上，请确保你正在使用正确的客户端，也许您的某些 KEYS 配置不当注册

• -tnsping 解决后测试你的 db_link:

  从 global_name@db_link 中选择 *；

您的数据库名称应该会出现!我希望这对您有所帮助