Django应用依赖循环 [英] Django App Dependency Cycle
问题描述
我正在开发一个Django应用程序,它具有相当复杂的模型(它建立大学 - 课程,模块,讲座,学生等)。
我将项目分解成应用程序,使整个事情更有条理(应用程序是课程,学校,人员,模块和时间段)。我有一个问题,一个应用程序中的模型可能依赖于另一个应用程序中的模型 - 所以我必须导入它。然后第二个应用依赖于第一个模型,所以有一个循环,Python会抛出一个错误。
人们如何处理这个?我明白应用程序应该是相对独立的,但是在这样的系统中,例如,使用ContentTypes将学生链接到一个模块是没有意义的。
<有没有人有类似的项目可以评论这个案例?
如果你的依赖是使用外键引用模型其他应用程序,您不要需要导入其他模型。您可以在ForeignKey定义中使用字符串:
class MyModel(models.Model):
myfield = models。 ForeignKey('myotherapp.MyOtherModel')
这样就不需要导入MyOtherModel,所以没有循环引用。 Django内部解析字符串,并且都按预期方式工作。
I am in the middle of developing a Django application, which has quite complicated models (it models a university - courses, modules, lectures, students etc.)
I have separated the project into apps, to make the whole thing more organised (apps are courses, schools, people, modules and timeperiods). I am having a problem whereby a model in one app may depend on a model in another - so I must import it. The second app then in turn depends on a model in the first, so there is a cycle and Python throws up an error.
How do people deal with this? I understand that apps should be relatively "independent", but in a system like this it doesn't make sense, for example, to use ContentTypes to link students to a module.
Does anyone have a similar project that could comment on this case?
If your dependency is with foreign keys referencing models in other applications, you don't need to import the other model. You can use a string in your ForeignKey definition:
class MyModel(models.Model):
myfield = models.ForeignKey('myotherapp.MyOtherModel')
This way there's no need to import MyOtherModel, so no circular reference. Django resolves the string internally, and it all works as expected.
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