Question

以下是我的模特：

class Model1(models.Model):
    ...
    distributor_links = GenericRelation(Relation, related_query_name="distributor_persons")

class Model2(models.Model):
    ...
    distributor_links = GenericRelation(Relation, related_query_name="distributor_groups")

class Model3(models.Model):
    pass

class Relation(models.Model):
    link = models.ForeignKey(Model3)

    content_type = models.ForeignKey(ContentType)
    object_id = models.PositiveIntegerField()
    content_object = GenericForeignKey('content_type', 'object_id')

现在我想获得与Model3对象关联的所有Model1或Model2对象。我的查询如下：

Model1.objects.filter(distributor_links=self.object)

其中self.object是Model3个实例。该查询引发错误：Cannot query "query": Must be "Relation" instance 我明白为什么它会抛出这个错误。这里distributor_links=self.object无法将Relation对象与Model3对象进行比较，但我仍然不知道如何编写我想要的查询。有什么想法吗？

Answer 1

Is it possible to resolve ContentType of object and use it and object id for filtering.

content_type = ContentType.objects.get_for_model(self.object)

Model1.objects.filter(distributor_links__content_type=content_type, distributor_links__object_id=self.object.id)

Answer 2

If self.object is a Model3 instance, you could:

Model1.objects.filter(distributor_links__link=self.object)

This quiestion is similar to: Django - How to use a filter with a foreign key field?

That is, the name of the field, followed by a double underscore (__), followed by the name of the field in the new model, and so on for as many models as you want to join.

For more information: https://docs.djangoproject.com/en/dev/ref/models/querysets/

如何在GenericRelation中按外键过滤？

2 个答案: