在Django模型中定义之前使用类 [英] Use a class before its definition in Django model

问题描述

当我尝试同步数据库时，出现错误菜单不是有效的类名称.

When I try to syncdb I get the error Menu is not a valid class Name.

我该如何解决这种情况:

How can I resolve that relationship case :

class MenuItem(model.Models)
    title = models.CharField(max_length=200)
    submenus = models.ManyToManyField(Menu, blank=True, null=True)

class Menu(Container):
    links = models.ManyToManyField(MenuItem)

推荐答案

来自 Django书:

如果需要在尚未创建的模型上创建关系定义后，您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:

例如:

class MenuItem(model.Models)
    title = models.CharField(max_length=200)
    submenus = models.ManyToManyField('Menu', blank=True, null=True)
                                      ^    ^

正如 Francis提到的(如

哪个模型具有ManyToManyField无关紧要，但是您应该只将其放在其中一个模型中，而不要同时放在两个模型中.

It doesn't matter which model has the ManyToManyField, but you should only put it in one of the models -- not both.

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