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djangodjango-modelsdjango-signals

Django, update rate, signals

class Thing (model.Models):
    name = models.CharField(max_length = 222)
    ratee = models.IntegerField(default = 0)
    ...

class Rate(models.Model):
    thing = models.ForeignKey(Thing)
    user = models.ForeignKey(User)
    rate = models.IntegerField()

If user evaluate the thing(give rate in Rate), I want to automatically calculate average and save to ratee in Thing. How to make it?

Solution

  • You can do

    class Rate(models.Model):

    def save(self, *args, **kwargs):
        super(Rate, self).save(*args, **kwargs)
        self.thing.ratee = Rate.objects.filter(thing=self.thing).aggregate(Avg('rate'))["rate__avg"]
        self.thing.save()