Question 120693 in Firebase Question posted in
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Firebase – In Firestore, how do I change for all documents of a collection of which a certain field has a certain value, that field in a certain value?

I want to change the value of a certain field of all documents in a Cloud Firestore collection to a certain value if that field is equal to a certain value. How do I do that?

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2

Answers


  1. 0
    1. Query with a filter that matches all of the documents you want to chage.
    2. Iterate the results of that query.
    3. Update each document with the new field value it should contain.
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  2. 0

    In addition to Doug’s answer, if you want to update all documents in a collection where a field contains a certain value, then please use the following lines of code:

    FirebaseFirestore db = FirebaseFirestore.getInstance();
Query query = db.collection("collName").whereEqualTo("fieldName", "fieldValue");
query.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
    @Override
    public void onComplete(@NonNull Task<QuerySnapshot> task) {
        if (task.isSuccessful()) {
            for (DocumentSnapshot document : task.getResult()) {
                document.getReference().update("fieldToUpdate", "value");
            }
        }
    }
});
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