Android - Firebase Firestore - Write the same document to different collections

Question

I have to write the same document to different collections, so I think that batched writes are not good for this. I would like to know if there is a function in firestore database, I expect written in javascript, that can copy a document I write once and paste it to different locations. These locations should be read from an array in the database.

Anyone could help me?

Thanks a lot and sorry for my low English.

Answer 1

The Batched writes in Cloud Firestore are meant for this exact purpose.

You can execute multiple write operations as a single batch that contains any combination of set(), update(), or delete() operations. A batch of writes completes atomically and can write to multiple documents.

And as a response to your question, yes, you can write the same document to different collections using this the batched writes operation.

And this how it looks like in code:

FirebaseFirestore rootRef = FirebaseFirestore.getInstance();
CollectionReference productsRef = rootRef.collection("products");
CollectionReference newProductsRef = rootRef.collection("newProductsRef");

WriteBatch writeBatch = rootRef.batch();
batch.set(productsRef.document(), yourObject);
batch.set(newProductsRef.document(), yourObject);

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

Using this code, you'll be able to write the same yourObject object to two different location in your Cloud Firestore database.