Is it possible to export the Firebase database and then make changes on an editor like Notepad and then import the database enforcing that only the changes made offline get updated? 

For example, say I export the database today and add 6000 new child nodes through my notepad and then two days I import the database back to update it with the new nodes without affecting the other updates that have been made by my users. 

What happens by default is that when I import the database it will rewrite every value that does not match. Hope I'm making sense.