如何从静态方法访问Django模型的反向外键？

Question

Suppose I have 3 Django models:

class MyModelA(models.Model):
    my_int = models.IntegerField()

    @staticmethod
    def my_Astatic_method():
        return "AHello"

class MyModelB(models.Model):
    my_int = models.IntegerField()
    my_a = models.ForeignKey(MyModelA, related_name="MyModelB_a")


    @staticmethod
    def my_Bstatic_method():
        return "BHello"

class MyModelC(models.Model):
    my_int = models.IntegerField()
    my_b = models.ForeignKey(MyModelB, related_name="MyModelC_b")

    @staticmethod
    def my_Cstatic_method():
        return "CHello"

I have an instance of MyModelA called a . From within a method of a , I would like to call my_Cstatic_method() . How can I do it?

a.MyModelB_a.model.my_Bstatic_method() works to call MyModelB 's static method. But I don't know how to get one level down into MyModelC 's static methods from MyModelB 's model attribute. How should I do it?

Surprisingly, there is no model attribute for the object a.MyModelB_a.model.MyModelC_b

Answer 1

After accessing model B from model A, you don't have model instance anymore, but model class.

With class, there is no fields but rather field descriptors, also for related fields, so there shoudl be MyModelC_b here:

a.MyModelB_a.model.MyModelC_b

but, as I said this isn't a field, but it have reference to related model as an sub-attribute in attribute related :

a.MyModelB_a.model.MyModelC_b.related.model

using that, you can now accss your static function from model C

a.MyModelB_a.model.MyModelC_b.related.model.my_Cstatic_method()