Add an item to a list in Firebase Database

Question

I have the following Firebase database structure. uIds is a type of List. I am trying to add another uId under uIds with

Answer 1

Adding 2 cents to Frank van Puffelen answer, you can use the key from push operation as a unique identifier of your request. Plus if you use hash map to update child then your DB will not be overridden

 // Create a node on Server and get key
  String requestID = AdminController.getInstance().referenceFromUrl
                        .child(END_POINT_REQUESTS)
                        .push().getKey();

  //use key as ID for your Object which you want to push as unique identifier of your model
  requestToPush.setRequestId(requestID );

 //Add updated Model Object in a Map to update DB instead of over writing
 requestsMap.put(requestID , requestToPush);

 //Update newly created DB nodes with data
   referenceFromUrl
            .child(END_POINT_REQUESTS)
            .updateChildren(productsMap,
                    new DatabaseReference.CompletionListener() {
                        @Override
                        public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {

                            if (databaseError != null) {
                                Log.e(TAG, "Error: Data could not be saved "
                                        + databaseError.getMessage());
                            } else {
                                Log.e(TAG, "Success : Data saved successfully.");
                            }
                        }
                    });

Result