Django 4.2.2导入错误：无法从django.contrib.auth.models导入Students

错误信息 #

Exception in thread django-main-thread:
Traceback (most recent call last):
  File "C:\Python39\lib\threading.py", line 950, in _bootstrap_inner
    self.run()
  File "C:\Python39\lib\threading.py", line 888, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Python39\lib\site-packages\django\utils\autoreload.py", line 64, in wrapper
    fn(*args, **kwargs)
  File "C:\Python39\lib\site-packages\django\core\management\commands\runserver.py", line 133, in inner_run
    self.check(display_num_errors=True)
  File "C:\Python39\lib\site-packages\django\core\management\base.py", line 485, in check
    all_issues = checks.run_checks(
  File "C:\Python39\lib\site-packages\django\core\checks\registry.py", line 88, in run_checks
    new_errors = check(app_configs=app_configs, databases=databases)
  File "C:\Python39\lib\site-packages\django\core\checks\urls.py", line 14, in check_url_config
    return check_resolver(resolver)
  File "C:\Python39\lib\site-packages\django\core\checks\urls.py", line 24, in check_resolver
    return check_method()
  File "C:\Python39\lib\site-packages\django\urls\resolvers.py", line 494, in check
    for pattern in self.url_patterns:
  File "C:\Python39\lib\site-packages\django\utils\functional.py", line 57, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "C:\Python39\lib\site-packages\django\urls\resolvers.py", line 715, in url_patterns
    patterns = getattr(self.urlconf_module, "urlpatterns", self.urlconf_module)
  File "C:\Python39\lib\site-packages\django\utils\functional.py", line 57, in __get__
    res = instance.__dict__[self.name] = self.func(instance)
  File "C:\Python39\lib\site-packages\django\urls\resolvers.py", line 708, in urlconf_module
    return import_module(self.urlconf_name)
  File "C:\Python39\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked       
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 790, in exec_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed     
  File "C:\Users\admin\Desktop\runapp\amsdjangocrud\urls.py", line 23, in <module>
    path('', include('amsapps.urls')),
  File "C:\Python39\lib\site-packages\django\urls\conf.py", line 38, in include    
    urlconf_module = import_module(urlconf_module)
  File "C:\Python39\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked       
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 790, in exec_module
  File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed     
  File "C:\Users\admin\Desktop\runapp\amsapps\urls.py", line 2, in <module>
    from . import views
  File "C:\Users\admin\Desktop\runapp\amsapps\views.py", line 4, in <module>       
    from django.contrib.auth.models import Students
ImportError: cannot import name 'Students' from 'django.contrib.auth.models' (C:\Python39\lib\site-packages\django\contrib\auth\models.py)

项目代码片段 #

models.py #

from django.forms import ModelForm, Textarea
from django.db import models

class Students(models.Model):
    student_id = models.IntegerField(primary_key=True)
    id_number = models.IntegerField(blank=True, null=True)
    firstname = models.CharField(max_length=50)
    lastname = models.CharField(max_length=50)
    gender = models.CharField(max_length=50)
    address = models.CharField(max_length=200)
    contact = models.IntegerField(blank=True, null=True)
    course = models.CharField(max_length=50)

    def __str__(self):
        return f'{self.course}, {self.contact}, {self.address}, {self.gender}, {self.lastname}, {self.firstname}, {self.id_number}, {self.student_id},'

class Assignment(models.Model):
    assignment_id = models.IntegerField(primary_key=True)
    assignment_name = models.CharField(max_length=50)
    instructor = models.ForeignKey('Instructor',on_delete=models.CASCADE)
    status = models.ForeignKey('Status',on_delete=models.CASCADE)
    subject = models.ForeignKey('Subject',on_delete=models.CASCADE)

    
    class Meta:
        managed = True
        db_table = 'assignment'

class Instructor(models.Model):
    instructor_id = models.IntegerField(primary_key=True)
    firstname = models.CharField(max_length=50)
    lastname = models.CharField(max_length=50)

    class Meta:
        managed = True
        db_table = 'instructor'

views.py（导入及相关函数） #

from django.contrib.auth.models import Students
from django.contrib.auth.models import Assignment

def main(request, id):
    joined_data = Assignment.objects.get(id>=1)
    return render(request, 'amsapp/main.html', {'data': joined_data })

admin.py（导入尝试） #

from .models import (
    Assignment,
    Instructor,
    Student,
    Subject
)

问题解决步骤 #

1. 修正模型导入路径
   views.py错误地从django.contrib.auth.models导入自定义模型，该模块是Django自带的认证模型库，没有你定义的Students和Assignment。需从当前app的models导入：

   # views.py 修正后
   from .models import Students, Assignment
   

2. 修正admin.py的导入错误

   • 模型类名是Students，但admin里写的是Student，名称不匹配；
   • Subject模型在models.py中未定义，需删除该导入，或在models.py中补充定义Subject和Status模型（Assignment模型关联了这两个）。
     修正后的admin.py：

   from .models import (
       Assignment,
       Instructor,
       Students
   )
   

3. 修正views中查询语句错误
   Assignment.objects.get(id>=1)会报错，get()用于获取单个对象，不能使用范围条件。若要获取所有id>=1的Assignment数据，改用filter()：

   def main(request, id):
       # 注意：Assignment模型主键是assignment_id，不是默认id，需用assignment_id__gte
       joined_data = Assignment.objects.filter(assignment_id__gte=1)
       return render(request, 'amsapp/main.html', {'data': joined_data })
   

   函数参数id未被使用，可根据需求删除或合理利用。

4. 补充缺失的模型
   Assignment模型关联了Status和Subject，但models.py中无这两个模型的定义，需补充：

   # 在models.py中添加
   class Status(models.Model):
       status_id = models.IntegerField(primary_key=True)
       status_name = models.CharField(max_length=50)
   
       class Meta:
           managed = True
           db_table = 'status'
   
   class Subject(models.Model):
       subject_id = models.IntegerField(primary_key=True)
       subject_name = models.CharField(max_length=50)
   
       class Meta:
           managed = True
           db_table = 'subject'
   

   补充后执行迁移命令：python manage.py makemigrations和python manage.py migrate

内容的提问来源于stack exchange，提问作者TryoutProgrammer