Summary of connection problems between sqlplus and Oracle

Question 1:

No listener is prompted during connectionProgram

There may be no listeners, or the service does not start.

1) create a listener:

2) if a listener already exists, it may be that the listener service does not start:

Question 2:

Sqlplus does not respond when connecting to the local database, as does when using the client (toad \ PLSQL Developer. And there is no response to the connection test with Oracle.

Recently, after starting the local Oracle service, you can use cmd to log on to sqlplus and find that the connection has no response problem, that is, it does not stop.

Under normal circumstances, the system will prompt that the connection has been established. The current situation is as follows:

After connect, run the carriage return command and there is no response. At the same time, the attempt to use the client does not respond.

From the service list, we can see that the Oracle service and the listening service are both normal:

At the same time, I did a connection test and did not respond:

Go to tnsnames. ora and check the configuration content.

After exploration, by deleting the original listener (using Oracle Net configuration assistant), it is normal to create a new listener, sweat. Delete the original listener and create a new listener. You will find that in the service list (services. MSC), the original listening service will be deleted and re-created. I guess the original listening service is invalid.