Query Django JSONFields that are a list of dictionaries - django

Question

Given a Django JSONField that is structured as a list of dictionaries:
# JSONField "materials" on MyModel:
[
{"some_id": 123, "someprop": "foo"},
{"some_id": 456, "someprop": "bar"},
{"some_id": 789, "someprop": "baz"},
]
and given a list of values to look for:
myids = [123, 789]
I want to query for all MyModel instances that have a matching some_id anywhere in those lists of dictionaries. I can do this to search in dictionaries one at a time:
# Search inside the third dictionary in each list:
MyModel.objects.filter(materials__2__some_id__in=myids)
But I can't seem to construct a query to search in all dictionaries at once. Is this possible?

Answer 1

Given the clue here from Davit Tovmasyan to do this by incrementing through the match_targets and building up a set of Q queries, I wrote this function that takes a field name to search, a property name to search against, and a list of target matches. It returns a new list containing the matching dictionaries and the source objects they come from.
from iris.apps.claims.models import Claim
from django.db.models import Q
def json_list_search(
json_field_name: str,
property_name: str,
match_targets: list
) -> list:
"""
Args:
json_field_name: Name of the JSONField to search in
property_name: Name of the dictionary key to search against
match_targets: List of possible values that should constitute a match
Returns:
List of dictionaries: [
{"claim_id": 123, "json_obj": {"foo": "y"},
{"claim_id": 456, "json_obj": {"foo": "z"}
]
Example:
results = json_list_search(
json_field_name="materials_data",
property_name="material_id",
match_targets=[1, 22]
)
# (results truncated):
[
{
"claim_id": 1,
"json_obj": {
"category": "category_kmimsg",
"material_id": 1,
},
},
{
"claim_id": 2,
"json_obj": {
"category": "category_kmimsg",
"material_id": 23,
}
},
]
"""
q_keys = Q()
for match_target in match_targets:
kwargs = {
f"{json_field_name}__contains": [{property_name: match_target}]
}
q_keys |= Q(**kwargs)
claims = Claim.objects.filter(q_keys)
# Now we know which ORM objects contain references to any of the match_targets
# in any of their dictionaries. Extract *relevant* objects and return them
# with references to the source claim.
results = []
for claim in claims:
data = getattr(claim, json_field_name)
for datum in data:
if datum.get(property_name) and datum.get(property_name) in match_targets:
results.append({"claim_id": claim.id, "json_obj": datum})
return results

Answer 2

contains might help you. Should be something like this:
q_keys = Q()
for _id in myids:
q_keys |= Q(materials__contains={'some_id': _id})
MyModel.objects.filter(q_keys)