I'm new in using EM and all oracle admin thing :) so could any one help or at least point me to a document that shows me the way:
I have 5 databases in 5 different hosts 2 of them 11g enterprise and 3 are XE.
My question is it possible to use EM in one of the enterprise databases to control and manage all my databases?
if so how? and if not what tool should I use?
From dbcontrol you can't monitor all these 5 database.
From Grid control Yes you can
Install the oms on of your machine, 12c cloud contol is latest release so please use the latest one.
install agent on each database host and you are done.
Please follow the doc to install oms/agent