I am getting data objects from Django models using
tabledata=Entity.objects.filter(quarter=1)
Using this method, I am able to extract the values of the objects specified by the foreign key like so
tabledata[0].creator.name
However when I changed the code to
tabledata=Entity.objects.filter(quarter=1).values()
I can extract only foreign key values but not the values of the object data linked with the foreign key. Something like
tabledata[0][creator][name] does not work
Is there a way to extract the values this way?
You can use lookup in .values()
like this:
entities = Entity.objects.filter(quarter=1).values('creator__name')
print(entities[0]['creator__name'])
You can fetch other fields too if you need:
Entity.objects.filter(quarter=1).values('creator__name', 'direct_field', 'another_direct_field')
This is one of the many reasons why using .values()
[Django-doc] is not a good idea: it erodes the logical layer of the model.
You can use .annotate(…)
[Django-doc] to add the name to the values:
from django.db.models import F
tabledata = Entity.objects.filter(quarter=1).annotate(
).values()
Then it will appear under the 'creator_name'
key in the dictionary.
But using .values()
is often only useful in specific usecases. For example a GROUP BY
on a specific value, or in a subquery. You should make use of serializers if you want to make JSON for a given model.
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