CODEWITHSUNDEEP
pythondjangopython-3.x
Moinuddin Girach
Moinuddin Girach

Reputation: 223

Django Query on parent from child

I am new to Python Django and I want to make a query 

class A(models.Model):
    foo = models.IntegerField(default=0)
    from_time = models.DateTimeField('start time')
    to_time = models.DateTimeField('end time')

class B(models.Model):
    model_a = models.ForeignKey(A, on_delete=models.PROTECT, related_name='model_a')
    model_c = models.ForeignKey(C, on_delete=models.PROTECT, related_name='model_c')

class C(models.Model):
    id = models.IntegerField(default=0)
    name = models.CharField(max_length = 20)

I want to make a query on class B where the current time is in between model_a.from_time and model_a.to_time. for that, I tried 

B.objects.filter(model_c=model_c_id, model_a.to_time__gte=start_date, model_a.to_time__lte=end_date)

it gives me syntax error SyntaxError: expression cannot contain assignment, perhaps you meant "=="?

Upvotes: 1

Views: 470

Answers (1)

iklinac
iklinac

Reputation: 15738

You are using wrong syntax to span relationship

B.objects.filter(model_c__id=model_c_id, model_a__to_time__gte=start_date, model_a__to_time__lte=end_date)

Upvotes: 2

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