AttRec | TensorFlow simple implemenation of AttRec model | Machine Learning library

I guess the problem here is that the monthKey is common which is 04 if I get it right, so by default Firebase consider it as the same child and will add everything under.

But back to the main question, Changing the pin, did you try this:

EDIT: Why don't you maybe change the structure of your database by using the unique id Firebase provide to each child added and use it as a key, then add a field in your child for the pin?

This will first of all make sure all your childs won't conflict later on if you have users with common PINs, second it will make it a lot easier to retrieve the whole user object on a temp object, change the PIN value in it, then push it again to the same child using the unique id provided!

If you're wondering how to get catch of this unique id, I also recommend saving it as a field in your object, save it while pushing your object, and retrieve from the retrieved temp object whenever needed.

Best way to handle all this is through the onChildAdded and onChildChanged methods not manually (HINT: Try to split your DB into different references, that will make it easier for you to manage ChildListener)