Django 3.1：OperationalError-没有此类列/表

Question

我整天都在解决这个问题。我在models.py中的代码如下：

from django.db import models
from django.contrib.auth.models import User
from users.models import TeacherProfile, StudentProfile

class Course(models.Model):
    name = models.CharField(max_length=100)
    desc = models.TextField()
    short_code = models.CharField(max_length=5)
    teacher = models.ForeignKey(TeacherProfile, null=True, on_delete=models.SET_NULL)
    students = models.ManyToManyField(StudentProfile)

    def __str__(self):
        return self.name

class Partition(models.Model):
    name = models.CharField(max_length=20)
    chunk = models.FloatField()
    result = models.FloatField(blank=True)
    course = models.ForeignKey(Course, on_delete=models.CASCADE)
    
    def __str__(self):
        return self.name
    
class Activity(models.Model):
    title = models.CharField(max_length=100)
    content = models.TextField()
    file = models.FileField(blank=True)
    course = models.ForeignKey(Course, on_delete=models.CASCADE)
    parent = models.ForeignKey(Partition, on_delete=models.CASCADE)

    def __str__(self):
        return self.title
    
class Grade(models.Model):
    grade = models.FloatField()
    remarks = models.CharField(max_length=200, blank=True)
    activity = models.ForeignKey(Activity, on_delete=models.CASCADE)
    student = models.ForeignKey(StudentProfile, on_delete=models.CASCADE)

我运行了以下命令：

python manage.py makemigrations
python manage.py migrate

根据我的研究，我甚至针对与此相关的其他StackOverFlow问题编写了以下命令：

python manage.py migrate --run-syncdb

仅课程表有效。活动和成绩表收到OperationalError-没有这样的列，而分区表得到了OperationalError-没有这样的表。

活动

OperationalError at /admin/course/activity/
no such column: course_activity.parent_id
Request Method: GET
Request URL:    http://127.0.0.1:8000/admin/course/activity/
Django Version: 3.1
Exception Type: OperationalError
Exception Value:    
no such column: course_activity.parent_id
Exception Location: C:\Users\hp\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\sqlite3\base.py, line 413, in execute
Python Executable:  C:\Users\hp\AppData\Local\Programs\Python\Python38-32\python.exe
Python Version: 3.8.5
Python Path:    
['C:\\Users\\hp\\Desktop\\TechKnow\\YowBro',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\python38.zip',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\DLLs',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\lib',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\lib\\site-packages']
Server time:    Fri, 21 Aug 2020 09:47:26 +0000

成绩

OperationalError at /admin/course/grade/
no such column: course_grade.remarks
Request Method: GET
Request URL:    http://127.0.0.1:8000/admin/course/grade/
Django Version: 3.1
Exception Type: OperationalError
Exception Value:    
no such column: course_grade.remarks
Exception Location: C:\Users\hp\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\sqlite3\base.py, line 413, in execute
Python Executable:  C:\Users\hp\AppData\Local\Programs\Python\Python38-32\python.exe
Python Version: 3.8.5
Python Path:    
['C:\\Users\\hp\\Desktop\\TechKnow\\YowBro',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\python38.zip',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\DLLs',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\lib',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\lib\\site-packages']
Server time:    Fri, 21 Aug 2020 09:47:28 +0000

分区

OperationalError at /admin/course/partition/
no such table: course_partition
Request Method: GET
Request URL:    http://127.0.0.1:8000/admin/course/partition/
Django Version: 3.1
Exception Type: OperationalError
Exception Value:    
no such table: course_partition
Exception Location: C:\Users\hp\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\sqlite3\base.py, line 413, in execute
Python Executable:  C:\Users\hp\AppData\Local\Programs\Python\Python38-32\python.exe
Python Version: 3.8.5
Python Path:    
['C:\\Users\\hp\\Desktop\\TechKnow\\YowBro',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\python38.zip',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\DLLs',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\lib',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32',
 'C:\\Users\\hp\\AppData\\Local\\Programs\\Python\\Python38-32\\lib\\site-packages']
Server time:    Fri, 21 Aug 2020 09:47:29 +0000

我做错了什么？

更新：我尝试将默认值添加到表中。可悲的是，它没有用。请帮助。

更新＃2：：我运行了python manage.py sqlmigrate course 0001。与实际站点中显示的错误相反，返回的SQL命令如下所示（我突出显示了用于创建表分区的SQL命令以进行强调）：

假设：：错误可能出在migration命令中。我从用于SQLite的数据库浏览器中手动删除了表。然后，我尝试运行makemigrations和migrations命令。尽管它迁移了SQL代码，但它根本不会创建任何东西。我们该如何解决？

我已解决问题！在下面检查我的答案。

Answer 1

您可以尝试在模型中添加相关名称，例如

$(table).on('length.dt')

Answer 2

我已解决问题。

多亏了kerasbaz，我在Django设置中检查了数据库配置。我认为我应该注释掉SQLite的配置并插入PostgreSQL。

所以我首先要做的是通过pgAdmin创建一个新数据库。现在，您需要安装pgAdmin和psycopg2（pip install psycopg2）。接下来，我在项目设置中编辑了数据库设置。

这是Django文档中的示例：

 DATABASES = {
     'default': {
            'ENGINE': 'django.db.backends.postgresql',
            'NAME': 'mydatabase',
            'USER': 'mydatabaseuser',
            'PASSWORD': 'mypassword',
            'HOST': '127.0.0.1',
            'PORT': '5432',
       }
}

最后，我运行了makemigrations和migrate命令。瞧！我解决了我已经解决了五个小时的问题。