The editor of Downcodes brings you a detailed guide on solving the ORA-12514 database connection error. The ORA-12514 error usually means that the client cannot connect to the Oracle database, which may be caused by an incorrect service name, listener problem, abnormal database service status, or network configuration error. This article will provide a series of troubleshooting steps to help you quickly diagnose and resolve such issues to restore your database connection.
The ORA-12514 error code usually indicates that the client cannot connect to the specified service in the Oracle database through the listener. The core steps to resolve this error include confirming the correctness of the service name (SERVICE_NAME), listener configuration, database service status check, and ensuring the correctness of the network configuration. In the detailed resolution steps, you usually need to check the tnsnames.ora and listener.ora files, restart the listening service, and verify that the database instance is running.
First, confirm that the service name you are trying to connect to is indeed the name configured in the database. This can be confirmed by viewing the tnsnames.ora file on the database server, which contains the network service names and their parameters required to connect to the database.
Check the tnsnames.ora file: Open the file, look for the database alias section, and confirm whether SERVICE_NAME is consistent with the one used when trying to connect. Test the connection using SQLPlus: Try a local connection using a connection string with SERVICE_NAME to determine if the service is reachable.The listener is an important component of the Oracle database network connection. If the listener is not configured correctly, or it is not running, an ORA-12514 error will result.
Check the listener.ora file: Make sure there is a corresponding service name and database instance in this configuration file. Listener status: Use the command lsnrctl status to check the status of the listener and confirm that the monitored service includes the correct SERVICE_NAME.The database instance must be running to accept connections through the listener. If the database service is not started, you need to start the service.
Check the database instance: Use sqlplus/as sysdba to connect to the database and execute the startup command to start the instance (if it has not been started yet). Automatic service registration: Ensure that the database service has automatically registered with the listener through the PMON process.The correctness of the network configuration is critical to successfully connecting to the database. The network configuration between the Oracle client and the database server must be set up correctly.
Ping command: Confirm that the client can reach the IP address of the database server. tnsping tool: Use the tnsping command and service name to test network connectivity and confirm that there are no problems with the network path.If there is a problem with the listening program, trying to restart the listening program may solve the ORA-12514 error.
Stop the listening program: Use lsnrctl stop to stop the currently running listening program. Start the listening program: Then use the lsnrctl start command to restart the listening program.If the listener does not update the status of the database service in real time, try letting it reload the configuration.
Reload the listener: Use the lsnrctl reload command to have the listener reload its configuration file, which often updates service status information.Incorrect permission settings or firewall rules may also cause the ORA-12514 error.
Operating system permissions: Make sure the user trying to perform the connection has the necessary permissions to connect to the database. Firewall settings: Check whether the firewall settings allow communication through the listener port.Oracle provides powerful logging and tracing tools that can help diagnose connection problems.
View the warning log: Oracle's warning log may contain additional information about failed attempts. Enable SQL*Net tracing: Configurable tracing parameters to obtain more detailed network connection attempt information.A small error in the client's connection string may result in an inability to connect.
Check the connection string format: Make sure all parameters in the connection string are correct, such as host, port and SERVICE_NAME. Use Easy Connect method: If possible, try to use Easy Connect (hostname:port/service_name) method to connect to reduce the complexity of the configuration file.By following these steps, most ORA-12514 errors can be resolved. Usually the problem is with the network configuration or the listener configuration. Be sure to double-check the configuration files and test your network connection, which can usually lead to finding the source of the problem and fixing it. If the problem is still not resolved, you may need to contact your database administrator or seek help from Oracle technical support.
What is the Ora-12514 error code? How to resolve this error?
The Ora-12514 error code is one of the Oracle database connection error codes and indicates that the requested Oracle service cannot be connected. To resolve this error, there are a few things you can try: Make sure the Oracle service is running: Check that the Oracle service has started correctly and make sure the database instance name matches the name used in the connection string. Check the listener configuration: Confirm that the listener in the listener configuration file (listener.ora) is correctly set to listen to the correct database instance. Check the network connection: Make sure the network connection between the client and the database server is normal and that the firewall is not blocking the database connection. Check TNS name resolution: Confirm whether the correct database connection information exists in the TNS name resolution file (tnsnames.ora). Check the connection string: Make sure the connection string contains the correct host name, port number, service name, or SID. If you still cannot resolve the Ora-12514 error code, please consult Oracle's official documentation or seek help from a professional database administrator.Why does the Ora-12514 error code appear? How to troubleshoot and solve?
The Ora-12514 error code may be caused by the following reasons: The Oracle service has not been started correctly or has been stopped: Check whether the Oracle service has been started correctly to ensure that the database can be connected. Listener configuration error: Verify that the listener settings in the listener configuration file are correct and that the database instance being listened to matches the name used in the connection string. Network connection failure: Check whether the network connection between the client and the database server is normal, and whether a firewall or other network device blocks the database connection. TNS name resolution issues: Verify whether the correct database connection information exists in the TNS name resolution file and ensure that the connection string can be correctly resolved to the correct database address. To troubleshoot and resolve the Ora-12514 error code, you can check the above possible causes one by one and take appropriate measures to fix it.How to avoid Ora-12514 error code?
To avoid the Ora-12514 error code, you can take the following measures: Regularly check and maintain the Oracle service: Ensure that the Oracle service is running normally, and perform regular system and database maintenance. Check the accuracy of the listener configuration: Make sure the listener settings in the listener configuration file (listener.ora) are correct and can listen to the correct database instance. Pay attention to the stability of the network connection: Ensure that the network connection between the client and the database server is normal, and regularly monitor network devices to ensure the stability of the connection. Confirm that TNS name resolution is correct: Verify that the database connection information in the TNS name resolution file (tnsnames.ora) is correct and update and maintain it regularly. Use reliable connection strings: Use the correct connection string in your application, making sure to include the correct host name, port number, service name, or SID. By following the above few measures, you can reduce or avoid the problem of Ora-12514 error code.Hope this article can help you solve the ORA-12514 error quickly. If the problem persists, seek help from a professional database administrator.