To access the Oracle Enterprise Manager Console from a client browser, the dbconsole process needs to be running on the server. This process is automatically started after installation. .
At the end of a successful database creation, Oracle Enterprise Manager(OEM) is automatically launched and the database is started. At other times, provided the dbconsole process is running on the server.
When Oracle DBA log in to the Oracle Enterprise Manager Database Control using the SYS or SYSTEM user account, Oracle DBA are logging in as the Oracle Enterprise Manager super user.