django: How to add extra field to all items in queryset - django

Question

My models looks this way
class Test(models.Model):
name = models.CharField(max_length=255)
test_plan = models.FK(TestPlan)
class TestPlan(models.Model):
name = models.CharField(max_length=255)
class Result(models.Model):
user = models.FK(User)
test_plan = models.FK(TestPlan)
test = models.FK(Test)
result = models.Boolean()
In the case I have a plan object in my view, I can access all tests by doing plan.test_set.all(). But is there a way to append all existing results to that query (so a result object is attached to a given test case, if it exists).
=====
I am trying to run the following
def get(self, request, *args, **kwargs):
task = get_object_or_404(Plan, id=kwargs.get('id'))
return render(request, self.template_name,
{"task": task})
def post(self, request, *args, **kwargs):
data = request.POST
task = get_object_or_404(Task, id=kwargs.get('id'))
tc = get_object_or_404(Test, id=data.get('tc_id'))
tc_result, _ = Result.objects\
.get_or_create(task=task, test=tc,
result=data.get('tc_result_status'))
return HttpResponse("OK")
And in template:
{% for test in task.tests_set.all %}
{{ test }}(here I want to render test result, if it I have one for given test in given plan, for current user)
{% endfor %}

Answer 1

You're looking to access a reverse one to many relationship? Just iterate in the same way you accessed tests_set.
{% for test in task.tests_set.all %}
{{ test }}
{% for result in test.result_set.all %}
{{ result }}
{% endfor %}
{% endfor %}

Answer 2

To filter the results in task.tests_set.all() or test.result_set.all() you need to use prefetch_related with custom Prefetch object.
Something like:
task = get_object_or_404(
TestPlan.objects.prefetch_related(
Prefetch('test_set', queryset=Test.objects.prefetch_related(
Prefetch('result_set', queryset=Result.objects.filter(user=request.user))
))
),
id=kwargs.get('id')
)
And in template:
{% for test in task.test_set.all %}
{% for result in test.result_set.all %}
{{ result }}
{% endfor %}
{% endfor %}