I'm working on an app that uses a firestore database with the following hierarchy: parent_collection: parent_document: subcollection: child_document{ string name} using collectionGroup I've been able to query subcollection for documents with a certain name, but I don't know how to get the parent_document
db.collectionGroup("subcollection").whereEqualTo("name", searchText).get()
.addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
if(task.isSuccessful()){
//here I want to get the parent id of all results
}
}
});
What is the best way to achieve that?
The QuerySnapshot
points to a number of QueryDocumentSnapshot
instances.
From a QueryDocumentSnapshot
, you can get the collection it's from with:
snapshot.getRef().getParent()
And then the parent DocumentReference
is:
snapshot.getRef().getParent().getParent()
So to get a subscollection of the parent document with:
snapshot.getRef().getParent().getParent().collection("name_of_subcollection")
Yes, I agree... that could've been a bit more readable. :)
You can get documents of a collection like this:
if(task.isSuccessful()) {
List<DocumentSnapshot> documents = task.getResult().getDocuments();
for(DocumentSnapshot documentSnapshot : documents) {
documentSnapshot.getId();
// or any field documentSnapshot.get(field);
}
}
You can write like this
List<DocumentSnapshot> documentSnapshotList = value.getDocuments();
for (DocumentSnapshot documentSnapshot : documentSnapshotList) {
DocumentReference dr = documentSnapshot.getReference().getParent().getParent();
// or any field documentSnapshot.get(field);
assert dr != null;
));
} //for end
In case you use stream:
docs = db.collection_group(u'collection_name').stream()
for doc in docs:
path = doc.reference.path # will get you the full path
# then you can manage the path as string
sub_path = path.split('/')[1]
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