код
from django.db import models

# Create your models here.
class Article(models.Model):
    article_title = models.CharField('название статьи', max_length = 200)
    article_text = models.TextField('текст статьи')
    pub_date = models.DateTimeField('дата публикации')

class Comment(models.Model):
    article = models.ForeignKey(Article, on_delete = models.CASCADE)
    author_name = models.CharField('имя автора', max_length = 50)
    comment_text = models.CharField('текст комментария', max_length = 300)
ошибка
$ python manage.py shell
Python 3.8.1 (tags/v3.8.1:1b293b6, Dec 18 2019, 22:39:24) [MSC v.1916 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from Site.models import Article, Comment
>>> Article.objects.all()
Traceback (most recent call last):
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\sqlite3\base.py", line 396, in execute
    return Database.Cursor.execute(self, query, params)
sqlite3.OperationalError: no such column: Site_article.pub_date

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\models\query.py", line 252, in __repr__
    data = list(self[:REPR_OUTPUT_SIZE + 1])
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\models\query.py", line 258, in __len__
    self._fetch_all()
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\models\query.py", line 1261, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\models\query.py", line 57, in __iter__
    results = compiler.execute_sql(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size)
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\models\sql\compiler.py", line 1144, in execute_sql
    cursor.execute(sql, params)
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\utils.py", line 100, in execute
    return super().execute(sql, params)
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\utils.py", line 68, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\utils.py", line 77, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\utils.py", line 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
    return self.cursor.execute(sql, params)
  File "C:\Users\Asus\AppData\Local\Programs\Python\Python38-32\lib\site-packages\django\db\backends\sqlite3\base.py", line 396, in execute
    return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such column: Site_article.pub_date