CODEWITHSUNDEEP
djangodjango-queryset
belonious
belonious

Reputation: 133

Trying filter query depending on a method of a related model

class Course(models.Model):

   def is_active(self):
      return self.enroll_set.count()>0

class CourseEvent(models.Model):

   course = models.ForeignKey(Course)

I want to find all Events that only point to active courses. something like:

events = CourseEvent.objects.filter(course.is_active=True)

thank you

Upvotes: 0

Views: 73

Answers (2)

christophe31
christophe31

Reputation: 6467

The answer is here: https://docs.djangoproject.com/en/dev/ref/models/querysets/#annotate

You make an annotation, it'll be filterable as a field.

It may look like this:

CourseEvent.objects.annotate(is_active=Count('course__enroll')).exclude(is_active=0)

Upvotes: 0

Henrik Andersson
Henrik Andersson

Reputation: 47222

Your is_active() method makes no sense.

is_active would imply a boolean of some sorts not 62. So there's something you can correct right off the bat. Normally, I would set a is_active flag on the Course model (thusly removing the method is_active altogether) and toggle that making the ORM call really straight forward:

class Course(models.Model):
    active = models.BooleanField(default=False)

events = CourseEvents.objects.filter(course__active=True)

Upvotes: 2

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