Django TypeError: isinstance() arg 2 must be a type or tuple of types

Posted 2021-01-07 yanxiatingyu

报错:

TypeError: isinstance() arg 2 must be a type or tuple of types

 

from django.db import models
from django.contrib.auth.models import AbstractUser
from blog.models import Blog

class UserInfo(AbstractUser):

    # identifier = models.CharField(max_length=40, unique=True)
    # USERNAME_FIELD = ‘identifier‘

    nid = models.AutoField(primary_key=True)
    # 手机号
    telephone = models.CharField(max_length=32)
    # 用户头像
    avatar = models.FileField(upload_to=‘avatar/‘, default=‘avatar/default.png‘)
    # # 用户创建时间
    # create_date = models.DateTimeField(auto_now_add=True)
    # # 用户博客--一对一对应博客表
    blog = models.OneToOneField(to=Blog, to_field=‘nid‘, on_delete=models.CASCADE, null=True)

 

blog app




from django.db import models
# Create your models here.
class Blog(models.Model):
    nid = models.AutoField(primary_key=True)
    # 博客名称
    title = models.CharField(max_length=32)
    # 站点名称
    site_name = models.CharField(max_length=32)
    # 博客主题样式
    theme = models.CharField(max_length=32)

 

当需要关联的表 不在同一个py文件下时 

　blog = models.OneToOneField(to="Blog", to_field=‘nid‘, on_delete=models.CASCADE, null=True)
这种写法是错误的， 因为django 无法当做一个模块来导入。所以会因为找不到 而报错。
但是所有class都在同一个py文件下，可以用“Blog” 这种方式导入