How to query complex firestore document (nested list of objects)? - firebase

Question

I have this document:
{
"artifact": {
"id": 1,
"tags" : [
"art",
"art2"
],
"origins": [
{
"id": 2,
"tags" : [
"o1",
"o11"
],
"origins": [
{
"id": 3,
"tags" : [
"o2",
"o3"
]
}
]
}
]
},
"insertionDate": "15022023095425"
}
I need to write a query to check if an id matches the id of the deepest origins object of another document.
At first, I thought something like this would work:
common_elements = db.collection("tasks").where("artifact.origins.origins.id", "==", current_item_id)
Is it possible to query object properties in a nested list with Firestore?
If this is not possible, how should I remodel my data?
Could I store origins objects in another collection and reference them in this document?

Answer 1

I need to write a query to check if an id matches the id of the deepest origins object of another document.
Using your actual database schema, you cannot perform such a query. If you only need to filter documents from the tasks collection by the deepest ID, then you should consider creating a non-nested field inside the document called deepestId, which in your example should contain the value of 3 and perform the following query:
common_elements = db.collection("tasks").where("deepestId", "==", 3)
If such a query can return multiple results, then you should add another where() call, to filter the documents based on the deepestId and the id like this:
common_elements = db.collection("tasks").where("deepestId", "==", 3).where("id", "==", 1)
Another possible solution would be to duplicate the data by creating another collection that should contain only the tasks with the deepestId == 3.