CODEWITHSUNDEEP
djangodjango-models
Yuval Adam
Yuval Adam

Reputation: 165182

Extending two related queries on same model in Django

Consider a Django model that forms a connection between two other model instances:

class User(models.Model):
    pass

class Meeting(models.Model):
    user_a = models.ForeignKey(User, related_name='a_meetings')
    user_b = models.ForeignKey(User, related_name='b_meetings')

Now suppose you want to define a function that returns all of a Users meetings, regardless of if he is side a or b. The naive implementation would be:

class User(models.Model):
    @property
    def meetings(self):
        return list(self.a_meetings.all()) + list(self.b_meetings.all())

What's the 'right' way to have this function return the matching QuerySet instead of a list? Bonus points for an elegant solution that doesn't use an ugly Q query ;)

Upvotes: 1

Views: 17

Answers (1)

Daniel Roseman
Daniel Roseman

Reputation: 599470

I think Qs are inevitable here.

The main principle with these things is always to start from the model you actually want to get: so since you want meetings, start there.

return Meeting.objects.filter(Q(user_a=self) | Q(user_b=self))

Upvotes: 2

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