[Answered ]-Sum of object fields in django

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Please don’t store the sum. This is duplicated data. It makes it harder to maintain consistency. Indeed, if you update dollars for example through a query, it will not update the total_amount.

You can use a property instead:

class Bet(models.Model):
    bet_id = models.AutoField(primary_key=True)
    event = models.ForeignKey(Event, on_delete=models.CASCADE, related_name='bet_event')
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    euros = models.IntegerField(default=0)
    rubles = models.IntegerField(default=0)
    dollars = models.IntegerField(default=0)
    max_amount = models.IntegerField(default=0)

    @property
    def total_amount(self):
        return self.euros + self.rubles + self.dollars

That being said, I don’t know if summing up amounts makes much sense. Summing up a dollar with a euro does not give us two dollars or two euros, that simply is a euro and a dollar.

👤willeM_ Van Onsem

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