Delete data from all the documents of sub collection with where condition in firestore

Question

I want to write a script that delete the data from all the documents of sub collection where status == expire. I have collection name user_data and this collection contain many documents all that documents contain sub collection name My_status and this My_status contains many documents, each document contains status and if status === expire than delete that data

The database structure is like this

collection - user_data
                     document1 - Subcollection - My_status --document1- Status expire      
                                                             document2 
                                                             document3

                     document2 - Subcollection - My_status --document1 
                                                             document2--Status expire
                                                             document3

I have tried this but this does not work as I can't relate it to sub collection

// First perform the query
db.collection('user_data').where('status','==',expire).get()
.then(function(querySnapshot) {
// Once we get the results, begin a batch
    var batch = db.batch();

    querySnapshot.forEach(function(doc) {
        // For each doc, add a delete operation to the batch
        batch.delete(doc.ref);
    });

    // Commit the batch
    return.batch.commit();
}).then(function() {
  // Delete completed!
  // ...
});

score 1 · Answer 1 · edited May 16 '19 at 19:53

Update: As of May, 2019, Cloud Firestore now supports collection group queries.

You can now query all the My_status sub-collections:

db.collectionGroup('My_status').where('','==', 'expire').get()
.then(function(querySnapshot) {

Original Answer

What you're trying to do now is known as a "collection group query", which is not currently supported. See Firestore query subcollections

If you're trying to delete all documents from the My_status sub-collections for all users, you will need to first loop over all users, and then query each of their subcollections:

db.collection('user_data').get()
.then(function(querySnapshot) {
  querySnapshot.forEach(function(userDocument) {
    userDocument.ref.collection("My_status").where('status','==','expire').get()
    .then(function(querySnapshot) {
      ...

Alternatively, you can store the data from all subcollections in a single global collection, and include the user ID as a field in there. That way you can query the single global collection to delete all expired documents.

Delete data from all the documents of sub collection with where condition in firestore

1 Answers1