Context: Using Django Rest Framework, I've created a ModelViewSet.
With these models:
class Claim(models.Model):
permalink = models.SlugField(max_length=255, blank=True, unique=True)
author = models.ForeignKey(get_user_model(), db_index=True, on_delete=models.SET_NULL, null=True, blank=True)
deleted = models.BooleanField(db_index=True, default=False)
collaborators = models.ManyToManyField(get_user_model(), through='ClaimCollaborator', through_fields=('claim', 'user'), related_name='claims')
# ...other fields
class ClaimCollaborator(models.Model):
claim = models.ForeignKey(Claim, db_index=True, on_delete=models.CASCADE)
user = models.ForeignKey(get_user_model(), db_index=True, on_delete=models.CASCADE)
access_project_only = models.BooleanField(default=True)
I'm trying to query Claim
to LEFT JOIN ClaimCollaborator
and bring back the access_project_only
field. ClaimCollaborator
is actually an intermediary model handling the ManyToMany relationship between claims and users (collaborators of the claim).
So far I have the following view (cut down for brevity):
class ClaimViewSet(viewsets.ModelViewSet):
permission_classes = (IsAuthenticated, )
serializer_class = serializers.ClaimSerializer
lookup_field = 'permalink'
def get_queryset(self):
return models.Claim.objects.filter(Q(author=self.request.user) | Q(claimcollaborator__user=self.request.user))
Serializer:
class ClaimSerializer(serializers.HyperlinkedModelSerializer):
author = serializers.PrimaryKeyRelatedField(allow_null=True, queryset=get_user_model().objects.all())
class Meta:
model = Claim
fields = ('url', 'permalink', 'author', 'deleted')
lookup_field = 'permalink'
extra_kwargs = {
'url': {'lookup_field': 'permalink'},
}
Listing produces this SQL:
SELECT "api_claim"."permalink", "api_claim"."author_id", "api_claim"."deleted"
LEFT OUTER JOIN "api_claimcollaborator" ON ("api_claim"."id" = "api_claimcollaborator"."claim_id")
WHERE ("api_claim"."author_id" = 39 OR "api_claimcollaborator"."user_id" = 39)
So I'm getting the LEFT JOIN on "api_claimcollaborator" (ClaimCollaborator) just fine, but none of the fields. I've tried .only(<claim fields>, 'claimcollaborator__access_project_only')
and .selected_related('claimcollaborator')
on the query but this just produces errors (I can be more specific about my attempts if that's helpful - just let me know).
I'm guessing this isn't so straightforward because the table in question is used as a ManyToMany within the ORM? Any help would be greatly appreciated.
You can use SlugRelatedField
on the serializer to indicate a field on a related model identified by a specific attribute.
class ClaimSerializer(serializers.HyperlinkedModelSerializer):
author = serializers.PrimaryKeyRelatedField(allow_null=True, queryset=get_user_model().objects.all())
claimcollaborator_set = serializers.SlugRelatedField(slug_field='access_project_only', read_only=True, many=True)
class Meta:
model = Claim
fields = ('url', 'permalink', 'claimcollaborator_set', 'author', 'deleted')
Firebase Cloud Functions: PubSub, "res.on is not a function"
TypeError: Cannot read properties of undefined (reading 'createMessageComponentCollector')
What is the best way to exclude exact one NumPy array entry from an operation? I have an array x containing n values and want to exclude the i-th entry when I call numpyprod(x)