'How to check if the field exists in firestore?

I am checking whether the Boolean field called attending exists, however I am not sure how to do that.

Is there a function such as .child().exists() or something similar that I could use?

firebaseFirestore.collection("Events")
    .document(ID)
    .collection("Users")
    .get()
    .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {
            if(task.isSuccessful()) {
                for(QueryDocumentSnapshot document: task.getResult()){
                    attending = document.getBoolean("attending");
                }
            }
        }
    });
javaandroidfirebasegoogle-cloud-firestore


Solution 1:[1]

What you're doing now is correct - you have to read the document and examine the snapshot to see if the field exists. There is no shorter way to do this.

Solution 2:[2]

You can do the following:

  if(task.isSuccessful()){
    for(QueryDocumentSnapshot document: task.getResult()){
       if (document.exists()) {
          if(document.getBoolean("attending") != null){
             Log.d(TAG, "attending field exists");
          }
        }
      }
  }

From the docs:

public boolean exists ()

Returns true if the document existed in this snapshot.

Solution 3:[3]

Here is how you can achieve it or you may have resolved already, this for any one searches for solution.

As per the documentation:

CollectionReference citiesRef = db.collection("cities");

Query query = citiesRef.whereNotEqualTo("capital", false);

This query returns every city document where the capital field exists with a value other than false or null. This includes city documents where the capital field value equals true or any non-boolean value besides null.

For more information : https://cloud.google.com/firestore/docs/query-data/order-limit-data#java_5

Solution 4:[4]

You can check firestore document exists using this,

CollectionReference mobileRef = db.collection("mobiles");
 await mobileRef.doc(id))
              .get().then((mobileDoc) async {
            if(mobileDoc.exists){
            print("Exists");
            }
        });

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Doug Stevenson
Solution 2 Community
Solution 3 Sumit yadu
Solution 4 Bhoomika Chauhan

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