A user may need to perform operation on a database target such as:
Monitor Performance Page
Review and administer AWR
Use SQL Access Advisor
Use SQL Tuning
In circumstances where a user is required to access database monitoring/management functions in Enterprise Manager but has not been given full SYSDBA access to database targets, you can create an Enterprise Manager administrator and give him the EM_USER and PUBLIC roles as well as, "Connect to any viewable target" privileges to the database targets that you want the administrator to access.
In the following steps we will grant "Connect to any viewable target" to all targets (instead of listing specific target instances). Depending on the type of authentication model being used, the administrator details will be stored in either the Cloud Control Repository or an external store, such as LDAP.