CODEWITHSUNDEEP
pythondjangodjango-modelsdjango-views
vikas devde
vikas devde

Reputation: 11751

How to get just one item from ForeignKey Model in django?

I have below two models in my app,

class Question(models.Model):
   question_text = models.CharField(max_length=200)
   question_author = models.ForeignKey(User, on_delete=models.CASCADE)
   q_pub_date = models.DateTimeField('Date Question Published')

   def __str__(self):
      return self.question_text


class Answer(models.Model):
   answer_text = models.CharField(max_length=5000)
   answer_author = models.ForeignKey(User, on_delete=models.CASCADE, related_name='ans_auth')
   question = models.ForeignKey(Question, on_delete=models.CASCADE)
   a_pub_date = models.DateTimeField('Date Answer Published')

   def __str__(self):
      return self.answer_text

I want to show latest questions on home page in a list. Each item in list will show question text and one answer out of many posted for that particular question. I am able to show question text but I am not able to find a way to get the answer item for every question item in my view below,

def home(request):
   latest_question = Question.objects.order_by('-q_pub_date')[:15]

Upvotes: 1

Views: 633

Answers (2)

Lemayzeur
Lemayzeur

Reputation: 8525

You could get the answer to a specific question with the reverse relation question_instance.answer_set.all() in views, {{ question_instance.answer_set.all }} in templates.

To select one answer, you can use slice, or first():

{{question_instance.answer_set.all.0 }} # templates

question_instance.answer_set.first() # views

If you want to add a new field votes to the Question and you want the answer which has highest votes?

A property method inside your question model will do it like: 

@property
def higher_answer(self):
    return self.answer_set.all().order_by('vote').last()

Upvotes: 0

Luan Fonseca
Luan Fonseca

Reputation: 1517

You can access all answers by using the related_name:

>>> question = Question.objects.get(question_text='random question')
>>> print(question.answer_set.all())

You can read more about this on: https://docs.djangoproject.com/en/2.0/ref/models/fields/#django.db.models.ForeignKey.related_name

Upvotes: 1

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