Django嵌套外键摘要

Question

我的Django 2.2项目中有以下模型：

class ModelA(models.Model):
    ModelA_id = models.UUIDField('ModelA ID', default = uuid.uuid4)

class ModelB(models.Model):
    ModelB_id = models.UUIDField('ModelB ID', default = uuid.uuid4)
    ModelA = models.ForeignKey(ModelA, on_delete=models.CASCADE)

class ModelC(models.Model):
    ModelC_id = models.UUIDField('ModelC ID', default = uuid.uuid4)
    ModelB = models.ForeignKey(ModelB, on_delete=models.CASCADE,)

class ModelD(models.Model):
    ModelD_id = models.UUIDField('ID', default = uuid.uuid4)
    ModelC = models.ForeignKey(ModelC, on_delete=models.CASCADE)
    user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)

如您所见，模型嵌套方式如下：

ModelD has FK to ModelC
ModelC has FK to ModelB
ModelB has FK to ModelA

如果我这样做：

ModelD.objects.filter(pk=0).select_related('ModelC__ModelB__ModelA')

这是否意味着在单个（或有限的）数据库请求中一次查询所有数据？我假设这也意味着它会将所有从ModelD开始的数据引用放入内存，对吗

我的最终目标是总结有多少个ModelD引用ModelC，哪些（不是多少）ModelC引用ModelB，最后是哪些ModelB引用ModelA