How to create/update multiple documents at once in Firestore

Question

Is it possible to store multiple documents in Firestore with only one request? With this loop it's possible but this would cause one save operation per item in the list.

for (counter in counters) {
    val counterDocRef = FirebaseFirestore.getInstance()
            .document("users/${auth.currentUser!!.uid}/lists/${listId}/counters/${counter.id}")
    val counterData = mapOf(
            "name" to counter.name,
            "score" to counter.score,
    )
    counterDocRef.set(counterData)
}

Answer 1

From Firebase documentation :

You can also execute multiple operations as a single batch, with any combination of the set(), update(), or delete() methods. You can batch writes across multiple documents, and all operations in the batch complete atomically.

// Get a new write batch
WriteBatch batch = db.batch();

// Set the value of 'NYC'
DocumentReference nycRef = db.collection("cities").document("NYC");
batch.set(nycRef, new City());

// Update the population of 'SF'
DocumentReference sfRef = db.collection("cities").document("SF");
batch.update(sfRef, "population", 1000000L);

// Delete the city 'LA'
DocumentReference laRef = db.collection("cities").document("LA");
batch.delete(laRef);

// Commit the batch
batch.commit().addOnCompleteListener(new OnCompleteListener<Void>() {
    @Override
    public void onComplete(@NonNull Task<Void> task) {
        // ...
    }
});

Firestore multiple write operations

Hope it helps..

Answer 2

Update some properties on all documents in a collection:

resetScore(): Promise<void> {
  return this.usersCollectionRef.ref.get().then(resp => {
    console.log(resp.docs)
    let batch = this.afs.firestore.batch();

    resp.docs.forEach(userDocRef => {
      batch.update(userDocRef.ref, {'score': 0, 'leadsWithSalesWin': 0, 'leadsReported': 0});
    })
    batch.commit().catch(err => console.error(err));
  }).catch(error => console.error(error))
}

Answer 3

void createServiceGroups() {
        List<String> serviceGroups = [];

        serviceGroups.addAll([
          'Select your Service Group',
          'Cleaning, Laundry & Maid Services',
          'Movers / Relocators',
          'Electronics & Gadget',
          'Home Improvement & Maintenance',
          'Beauty, Wellness & Nutrition',
          'Weddings',
          'Food & Beverage',
          'Style & Apparel',
          'Events & Entertainment',
          'Photographer & Videographers',
          'Health & Fitness',
          'Car Repairs & Maintenance',
          'Professional & Business Services',
          'Language Lessons',
          'Professional & Hobby Lessons',
          'Academic Lessons',
        ]);
        Firestore db = Firestore.instance;
        // DocumentReference ref = db
        //     .collection("service_groups")
        //     .document(Random().nextInt(10000).toString());

        // print(ref.documentID);

        // Get a new write batch

        for (var serviceGroup in serviceGroups) {
          createDocument(db, "name", serviceGroup);
        }

        print("length ${serviceGroups.length}");
      }

      createDocument(Firestore db, String k, String v) {
        WriteBatch batch = db.batch();
        batch.setData(db.collection("service_groups").document(), {k: v});
        batch.commit();
      }

---

   createDocument(Firestore db, String k, String v) {
            WriteBatch batch = db.batch();
            batch.setData(db.collection("service_groups").document(), {k: v});
            batch.commit();
          }

---

This may help you:

 for (var serviceGroup in serviceGroups) {
      createDocument(db,  "name", serviceGroup  );
    }

Answer 4

If you are in the need to use add() instead of set, please follow the code below,

public void createMany(List<T> datas) throws CustomException {
    Firestore firestore = connection.firestore();
    CollectionReference colRef = firestore.collection("groups");

    WriteBatch batch = firestore.batch();
    for (T data : datas) {
        batch.create(colRef.document(), data);
    }

    ApiFuture<List<WriteResult>> futureList = batch.commit();
    try {
        for (WriteResult result : futureList.get()) {
            logger.debug("Batch output: {}", result.getUpdateTime());
        }
    } catch (InterruptedException | ExecutionException e) {
        throw new CustomException(500, e.getMessage());
    }
}

This might be useful when you are in the need to generate the id from the firestore db.