[SOLVED] Django annotation from different sources

Django annotation from different sources

I'm trying to build following annotation, essentially looking up the nin field from a person either from the IDcard or from the Person model.

.annotate(
       checkins_scan=Scan.objects.filter(models.Q(nin=OuterRef("person__idcard__nin") | models.Q(national_number=OuterRef("person__nin")))
       .values(
           data=JSONObject(id="id", nin="nin", datetime="datetime")
       )[:1]
)

However, I get following error:

NotImplementedError: Use .bitand(), .bitor(), and .bitxor() for bitwise logical operations.

Looks like I'll need bitor(), but I'm not getting any further with the basic examples I'm finding (e.g. documentation here).

When I try to work with F() I get TypeError: F.__init__() got an unexpected keyword argument 'nin'.

Any clues on how to properly do this?

Solution

You need to use a Subquery ^[Django-doc], and the parenthesis did not fully match.:

from django.db.models import OuterRef, Subquery

MyModel.objects.annotate(
    checkins_scan=Subquery(
        Scan.objects.filter(
            models.Q(nin=OuterRef('person__idcard__nin'))
            | models.Q(national_number=OuterRef('person__nin'))).values(
                data=JSONObject(id='id', nin='nin', datetime='datetime')
        )[:1]
    )
)