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

63

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):
    cart = models.ForeignKey(Cart)
    add_date = models.DateTimeField(auto_now_add=True)
    order_number = models.IntegerField()
    enable = models.BooleanField(default=True)

How do I make the IntegerField auto increment?

This question is tagged with python django django-models

~ Asked on 2014-01-15 04:01:50

The Best Answer is


91

In Django

1 : we have default field with name "id" which is auto increment.
2 : You can define a auto increment field using AutoField field.

class Order(models.Model):
    auto_increment_id = models.AutoField(primary_key=True)
    #you use primary_key = True if you do not want to use default field "id" given by django to your model

db design

+------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table      | Create Table                                                                                                                                                  |
+------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------+
| core_order | CREATE TABLE `core_order` (
  `auto_increment_id` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`auto_increment_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.01 sec)

If you want to use django's default id as increment field .

class Order(models.Model):
    dd_date = models.DateTimeField(auto_now_add=True)

db design

+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table       | Create Table                                                                                                                                                    |
+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------+
| core_order | CREATE TABLE `core_order` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `dd_date` datetime NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------+

~ Answered on 2014-01-15 06:06:29


23

In django with every model you will get the by default id field that is auto increament. But still if you manually want to use auto increment. You just need to specify in your Model AutoField.

class Author(models.Model):
    author_id = models.AutoField(primary_key=True)

you can read more about the auto field in django in Django Documentation for AutoField

~ Answered on 2016-01-19 08:58:18


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