Oracle Error ORA-12154: TNS:could not resolve the connect identifier specified

Oracle Error Message

ORA-12154: TNS:could not resolve the connect identifier specified

Reason for the Error

The Oracle error “ORA-12154: TNS:could not resolve the connect identifier specified” is a common message.

When this happens, there is a problem connecting to one of your Oracle services or database instances.

This error may be referred to as “ORA-12154: TNS:could not resolve service name” in some Oracle database versions.

The listener configuration, your local copy of the tnsnames.ora file, and your database name aliases are all often encountered errors that all share the same root cause—ORA-12154.

Solution

– 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. See the Oracle Net Services

Administrators Guide or the Oracle operating system specific guide for more information on naming.