How do I make an auto increment integer field in Django?

Question

I am making an Order model for a shopping cart and I need to make a field that auto increments when the order is made:

class Order(models.Model)         


        

Answer 1

You can override Django save method official doc about it.

The modified version of your code:

class Order(models.Model):
    cart = models.ForeignKey(Cart)
    add_date = models.DateTimeField(auto_now_add=True)
    order_number = models.IntegerField(default=0)  # changed here
    enable = models.BooleanField(default=True)

    def save(self, *args, **kwargs):
        self.order_number = self.order_number + 1
        super().save(*args, **kwargs)  # Call the "real" save() method.

Another way is to use signals. More one:

1. official Django docs about pre-save
2. stackoverflow example about using pre-save signal