在Django中创建其他对象后如何自动创建新对象？ [英] How create new object automatically after creating other object in django?

问题描述

例如，我有两个课程。

class Book(models.Model):
    title = models.CharField (...)    
    author = models.CharField (...)
    price = models.Integer(...)

class Order(models.Model)
    order_datetime = models.DateTimeField()
    order_book = models.ForeignKey(Book,....)

在数据库中每次添加新Book对象后，应自动创建

新订单对象。并自动将order_book字段与相应的书本对象完成。

New Order object should be created automatically after each addition of a new Book object in the database. And order_book fielt should be autocomplited with correspending book object.

我该怎么做？

感谢

推荐答案

您可以覆盖Book的保存方法：

You can override the save method of Book:

class Book(models.Model):
    title = models.CharField (...)    
    author = models.CharField (...)
    price = models.Integer(...)

    def save(self, *args, **kwargs):
        is_new = True if not self.id else False
        super(Book, self).save(*args, **kwargs)
        if is_new:
            order = Order(order_book=self)
            order.save()

如果应该用插入时间填充auto_now_add = True，也可以将它添加到order_datetime：

You can also add auto_now_add=True to order_datetime if it's supposed to be filled with insertion time:

order_datetime = models.DateTimeField(auto_now_add=True)

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