CODEWITHSUNDEEP
djangodjango-modelsdjango-queryset
Cobblepot
Cobblepot

Reputation: 59

Filtering ManyToManyField

I can't make a simple query working although I follow the docs https://docs.djangoproject.com/en/dev/topics/db/queries/#field-lookups.

models.py

class Course(models.Model):
    name = models.CharField(max_length=30, unique=True, blank=False)    
    code = models.CharField(max_length=10, unique=True, blank=False)

    def __str__(self):
        return self.name

class User(models.Model):
    ...
    courses = models.ManyToManyField(Course)

I registered an user, whose name is "a" and a course, which is called "mathématique" but I got this in the shell :

>>> User.objects.all()
[<User: a>]

>>> User.objects.filter(courses__name__contains='mathématique')
[]

>>> User.objects.filter(courses__name__in='mathématique')
[]

It always return an empty list and I can't understand why. When I see the administration I can see a User who has a "mathématique" course.

EDIT

forms.py

from user.models import User, Course

class UserForm(forms.ModelForm):
    cours_choices = forms.ModelChoiceField(queryset=Course.objects.all())
    class Meta:
        model = Offer
        fields = ('cours_choices', 'faculty', 'description')

EDIT2

Okay, the problem is solved. The above queries works fine. I don't know why it's working now but I suspect the culprit could be a confusion about the name "cours", which was used for the class and the field

Upvotes: 0

Views: 125

Answers (1)

Dariusz Krynicki
Dariusz Krynicki

Reputation: 2718

What if you remove "course = models.ManyToManyField(Course)" from class User and move it to class Course as follows "course = models.ManyToManyField(User)" and do following query:

User.objects.filter(course__name__contains='mathématique')

please note I have changed (Course) to (User)

Upvotes: 1

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