django - 为什么将管理器声明为 Django 模型，无效 "objects"

Question

我已经声明了以下模型的经理，但这样做后，我不能再使用 List.objects.get() .有人知道为什么吗？

class List(models.Model):
  title = models.CharField(max_length=20, unique=True)
  archived = models.BooleanField()

  archived_lists = ArchivedListManager()
  active_lists = ActiveListManager()

和经理:

class ArchivedListManager(models.Manager):
  def get_query_set(self):
    return super(ArchivedListManager, self).get_query_set().filter(archived=True)

class ActiveListManager(models.Manager):
  def get_query_set(self):
    return super(ActiveListManager, self).get_query_set().filter(archived=False)

错误是 type object 'List' has no attribute 'objects'

Answer 1

如 Django docs 中所述:

If you use custom Manager objects, take note that the first Manager Django encounters (in the order in which they're defined in the model) has a special status. Django interprets the first Manager defined in a class as the "default" Manager, and several parts of Django will use that Manager exclusively for that model. As a result, it's a good idea to be careful in your choice of default manager in order to avoid a situation where overriding get_query_set() results in an inability to retrieve objects you'd like to work with.

因此，就“为什么”而言，它允许您提供自己的默认管理器。

不过，解决方案很简单:只需添加这个

objects = models.Manager()

到您的模型类。