How to check if the field exists in firestore?

Question

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"); } } } });

Community · Accepted Answer · 2020-06-20 09:12:55Z

5

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.

edited Jun 20, 2020 at 9:12

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answered Oct 1, 2019 at 8:13

Peter Haddad

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3 Comments

Daniel Saito Over a year ago

I think OP is asking about how to check the existence of a Field inside a document, not a document itself.

Peter Haddad Over a year ago

@DanielSaito Yes, but you cannot only retrieve a field alone. You can only retrieve a document, so this is the best way, get the document then check if the field is null.

Daniel Saito Over a year ago

yeah, but I think OP is talking after get the document, doing the doc[index].get(field) of a list of documents where some docs have this field and other don't, I think is a good example that converges to the same error that OP is struggling haha, sorry if I'm not very clear in my explanations.

Doug Stevenson · Accepted Answer · 2019-10-01 08:09:37Z

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.

Sumit yadu · Accepted Answer · 2022-02-08 13:51:46Z

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

Noman Shaikh · Accepted Answer · 2022-09-18 16:48:33Z

I use following boolean method may be someone else can

for(QueryDocumentSnapshot document: task.getResult()){ if(document.contains("attending")){ attending = document.getBoolean("attending"); } }

Nicolas · Accepted Answer · 2023-02-17 17:00:26Z

I didn't find any solution so what I do is a try - catch (sorry Flutter / Dart, not java):

 bool attendingFieldExists = true; DocumentSnapshot documentSnapshot = // your Document Query here await FirebaseFirestore.instance .collection('collection') .doc(FirebaseAuth.instance.currentUser?.uid) .get(); // trying to get "attending" field will throw an exception // if not existing try { documentSnapshot.get("attending"); } catch (e) { attendingFieldExists = false; print("oops.. exception $e"); }

Then you can adapt the code you want to apply depending on attendingFieldExists. I'm new to Flutter / Dart so not sure this is the best way to handle this.. but it works for me.

Vincy · Accepted Answer · 2023-10-13 17:43:42Z

instead of documentSnapshot.get("attending"); do this documentSnapshot.ContainsField("attending");

If the field exists it will return true else returns false.

Sergio Samaan · Accepted Answer · 2024-06-05 21:16:18Z

How about using:

QueryDocumentSnapshot<Map<String, dynamic>> data = 'some data'; if (data.data().containsKey(fieldName)) { // do something. }

awariat · Accepted Answer · 2024-10-04 11:40:39Z

You can use hasOwnProperty

if (docSnap.exists()) { ... if (docSnap.data().hasOwnProperty('myField')) { ... } else { console.log("No such field!"); } } else { console.log("No such document!"); }

Bhoomika Chauhan · Accepted Answer · 2021-07-21 14:05:07Z

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"); } });

of what I understood, OP is asking about a field inside a doc, not a doc itself, test if a field exists inside a doc. I have the same issue.

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