Database reference 

Essentially, a reference to the database is required. Every Firebase project has its own particular devoted Realtime Database items of which can be examined by opening the project inside the Firebase console and picking the Database option. Inside the console, panels can be selected to show data trees set away in the database, the rules outlined for fetching the access, database use estimations, and so on. 

Firebase databases are usually Representational State Transfer (REST) endpoint references, which we will use to add the data. We will understand how to fetch the reference with the following code snippet:

// fetch reference database
FirebaseDatabase mDatabase = FirebaseDatabase.getInstance();
DatabaseReference mDbRef = mDatabase.getReference("Donor/Name");

The preceding code will fetch the reference, on the off chance that the particular path does not exist now, it is composed automatically inside the tree when data is written at that location.