Can we maintain files having Database settings in other than App.config and Web.cofig files ?
Yes, I do know that we can write the code in the application. But I want to maintain these Db settings xml files (config) files outside App.config or web.config.
If its possible how to use maintain these files and how to use them in our application.

You can put your configuration settings in a XML file and call cfg.Configure() (if the file is "hibernate.cfg.xml") or cfg.Configure("PathToYourXmlFile").