Firebase Firestore, get the reference document inside another document

Question

I\'m using Firebase Cloud Firestore, I want when I\'m getting a document with reference field inside to receive the reference field as a document and not as a r

Answer 1

You can get multiple documents from a collection. Read get mutiple documents section from documentation

Here's an example

db.collection("classes")
    .document(idOfTheClassYouWantToGet)
    .collection("users")
    .get()
    .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>(){
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {
            if (task.isSuccessful()) {
                for (DocumentSnapshot document : task.getResult()) {
                    User user = document.toObject(Users.class);
               }
            } 
        }
    });

Answer 2

You can't instruct the Firestore client SDK to automatically follow document references during a fetch of a single document. You have to request each individual document. In other words, there is no "join" operation like you might expect in SQL.

See also: What is firestore Reference data type good for?