如何在Django中创建自动递增整数字段？ [英] How do I make an auto increment integer field in Django?

问题描述

我正在为购物车制作 Order 模型，我需要创建一个在下订单时自动递增的字段：

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)

如何使 IntegerField 自动递增？

推荐答案

在Django

1中：我们有默认字段，名称为 id

2：您可以使用 AutoField
字段定义一个自动递增字段。

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设计

+------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 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)

如果要使用django的默认ID作为增量字段。

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

db设计

+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------+
| 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 |
+-------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------+

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