If you want to manage database instances with the Database Manager GUI, then they have to be registered.
If you want to access a remote database instance with the Database Manager, you have to start the X Server on the relevant database server.
...
1. Choose Instance ® Register Instance.
2.
Enter the
name of the database server.
Confirm this by choosing Add Server.
3. Select the database instances that you want to register, and confirm.
The database instance has been registered and from now on it appears on the list of registered databases.
You can organize the way in which the database instances are stored and appear in the Database Manager GUI according to your requirements.
To be able to manage a database instance, you must set up a connection to the DBM server.