Handling aggregate objects

[Venefilyn]

In my application right now I've been aggregating database entries and serving them in a REST API. Though when it comes to graphene I've not had any luck getting aggregates to works. Any help would be thankful

Current code:

aggregated_snapshots = DjangoFilterConnectionField(IssueSnapshotNode)

def resolve_aggregated_snapshots(self, info, **kwargs):
    return IssueSnapshot.objects.order_by() \
        .values('status', type=F('issue__type_name')) \
        .annotate(status_count=Count('status'))

Error message returned:

Merging 'QuerySet' classes must involve the same values in each case

[zbyte64]

Looks like issue #758

[Venefilyn]

Probably. Before the latest update I also tried to do this, though at that time I got a different error I don't remember at the moment

[zbyte64]

After some digging, you might want to try replacing values with only or defer. PR #796 revealed how the two are treated differently and that values delivers dictionaries while graphene_django want's django instances.

[Venefilyn]

Maybe this is just my inexperience, but from what I can see getting a field from a related model issue__type_name won't work with only() as it will only show you the Issue model, not the type_name.

So I'm unsure how this can work in practice for aggregating. values() would work as it took the value of issue.type_name and GROUP BY that

[zbyte64]

Sounds like we might want the filtering functionality of DjangoFilterConnectionField but with the option to change the type. Might be able to subclass and override node_type as well as type ...

[Venefilyn]

I'm not well into the library implementation, what does node_type and type represent and affect?

[zbyte64]

I believe node_type is the inner type that the connection field connects to, type adds wrappings, basically just NotNull with a type check which ensures we are connecting it to a django object type.

[Venefilyn]

Yeah, this has been a bit over my head. Not been successful with aggregating based off of a relation of issue__type_name

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[Venefilyn]

Not had any success yet, still something I'd like to solve