Balatharan,
This is now all fully configurable:
https://github.com/orbeon/orbeon-forms/wiki/Form-Runner:-Buttons-and-ProcessesSo yes, Save does save to the database.
The notion of "drafts" has changed with the autosave feature:
https://github.com/orbeon/orbeon-forms/wiki/Form-Runner:-AutosaveAutosave only works with logged in users so that deals with that issue.
On the other hand the current save-draft button just saves the data as usual, it's just that it doesn't check whether the data is valid first.
-Erik