django model reference, Add more contraint to reference - django

Question

I have a question about Django model references.
I want to add more constraints to a ForeignKey or ManytoManyField like this:
question_id = models.ManyToManyField(Question(open==True))
Or put another similar constraint:
Actually I don't want to show a question that is not open as a selection( heightened in Answer form like the image above),
of course, I have done it by some query but does Django has any built-in support for it? I have tried some other way but it didn't work. Thanks!
class Answer(models.Model):
"""Give answers"""
answer = models.TextField()
question_id = models.ManyToManyField(Question(open==True))
upVote = models.IntegerField(default=0)
downVote = models.IntegerField(default=0)
def __str__(self):
"""return string """
return self.answer

Answer 1

While you still can, change your model relations. What you have now is that an answer can be linked to multiple questions. However, answer contains up and down vote.
So I can create two questions:
Is 1 + 1 two?
yes
no
Is 1 + 1 three?
yes
no
I can link the answers "yes" and "no" to both questions, which can be convenient with a good interface and is normalized. But they will share the up/down votes. Instead, answer should have a foreign key to question, because an answer can only be linked to one question at a time, even if the answer text is identical to prevent sharing of the up and down votes.
Secondly, we generally don't name fields question_id, but question:
From an object relation perspective, you relate an answer to a question not to a question id. (Under the hood, question_id is created to allow faster lookups and to serve as field name in the underlying database table).
On to your actual problem: you want to limit the available choices, which is what limit_choices_to does for you. So you would end up with this:
class Answer(models.Model):
"""Give answers"""
answer = models.TextField()
question = models.ForeignKey(
Question, on_delete=models.CASCADE, related_name='answers',
limit_choices_to={'open': True},
)
upVote = models.IntegerField(default=0)
downVote = models.IntegerField(default=0)
def __str__(self):
"""return string """
return self.answer
# Serializer
class AnswerSerializer(serializers.ModelSerializer)
class Meta:
model = Answer
fields = ('answer', 'upVote', 'downVote', 'question_id')
As you can see, your serializer can reference the magic field question_id.