Django模型：两个类之间的相互引用，并且不可能在python中使用前向声明 [英] Django models: mutual references between two classes and impossibility to use forward declaration in python

问题描述

我已经定义了两个模型，其中每个引用另一个，如下所示：

I have defined two models where each one references the other, like so:

class User(models.Model):
    # ...
    loves = models.ManyToManyField(Article, related_name='loved_by')

class Article(models.Model):
    # ...
    author = models.ForeignKey(User)

你看，问题是类引用彼此。无论以什么顺序执行这两个类，python总是引发 NameError 异常，抱怨一个类没有定义。

You see, the problem is both classes references each other. No matter in what order these two classes are implemented, python always raises NameError exception, complaining either one class is not defined.

推荐答案

您可以在 docs ：

如果您需要在尚未定义的模型上创建关系，则可以使用模型的名称，而不是模型对象本身：

If you need to create a relationship on a model that has not yet been defined, you can use the name of the model, rather than the model object itself:

class Car(models.Model):
    manufacturer = models.ForeignKey('Manufacturer')
    # ...

class Manufacturer(models.Model):
    # ...

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