Django：AttributeError：类型对象'Position'没有属性'_meta'

Question

我有一个用户模型和一个职位模型，其中职位和用户模型都有用户名和职位名称作为唯一键。我想创建一个单独的表（这将是一个关系表），我可以将每个用户与他们的位置相关联。这是我尝试过的：class Profile(models.Model):    STATUS_CHOICES = (    (1, ("Permanent")),    (2, ("Temporary")),    )    GENDER_CHOICES = (    (1, ("Male")),    (2, ("Female")),    (3, ("Not Specified"))    )    user = models.OneToOneField(User, on_delete=models.CASCADE)    emp_type = models.IntegerField(choices=STATUS_CHOICES, default=1)    contact = models.CharField(max_length=13, blank=True)    whatsapp = models.CharField(max_length=13, blank=True)    gender = models.IntegerField(choices=GENDER_CHOICES, default=3)    avatar = models.ImageField(upload_to='users/images', default='users/images/default.jpg')    manager_username = models.ForeignKey(User, blank=True, null=True, to_field='username',related_name='manager_username', on_delete=models.DO_NOTHING)    def __str__(self):        return self.user.usernameclass Position:    name = models.CharField(max_length=20, unique=True)class Emp_position:    emp_uname = models.ForeignKey(User, related_name='emp_name', to_field='username', on_delete=models.CASCADE)    position_name = models.ForeignKey(Position, related_name='position', to_field='name', on_delete=models.CASCADE)在我迁移 Position 表之前它工作正常，但是当我添加关系表即 Emp_position 时，我收到一个错误：Traceback (most recent call last):  File "C:\Users\Himanshu Poddar\AppData\Local\Programs\Python\Python36-32\lib\site-packages\django\db\models\fields\related.py", line 786, in __init__    to._meta.model_nameAttributeError: type object 'Position' has no attribute '_meta'During handling of the above exception, another exception occurred:Traceback (most recent call last):  File "manage.py", line 15, in <module>    execute_from_command_line(sys.argv)为什么我会收到此错误，我该如何解决？

Answer 1

你忘了继承 models.Model 类。

class Position(models.Model):

    name = models.CharField(max_length=20, unique=True)

class Emp_position(models.Model):

    emp_uname = models.ForeignKey(User, related_name='emp_name', to_field='username', on_delete=models.CASCADE)

    position_name = models.ForeignKey(Position, related_name='position', to_field='name', on_delete=models.CASCADE)