django.db.utils.OperationalError: no such table: chat_contact

[GeonwooVincentKim]

Hi. I made models.py by watching your video, but I'm not sure how to solve this problem.
First of all, when I access to 127.0.0.1:8000/admin/chat/chat/add,
It shows

django.db.utils.OperationalError: no such table: chat_contact

This is my models.py, and I migrated and deleted this models.py for several times.

from django.contrib.auth import get_user_model
from django.db import models

User = get_user_model()


# Create your models here.
class Contact(models.Model):
    user = models.ForeignKey(User, related_name='friends', on_delete=models.CASCADE)
    friends = models.ManyToManyField('self', blank=True)

    def __str__(self):
        return self.user.username


class Message(models.Model):
    contact = models.ForeignKey(Contact, related_name='messages', on_delete=models.CASCADE)
    content = models.TextField()
    timestamp = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return self.contact.user.username


class Chat(models.Model):
    participants = models.ManyToManyField(Contact, related_name='chats')
    messages = models.ManyToManyField(Message, blank=True)

    def last_10_messages(self):
        return self.messages.objects.order_by('-timestamp').all()[:10]

    def __str__(self):
        return "{}".format(self.pk)

And this is the Error Occurs.

Environment:
Request Method: GET
Request URL: http://127.0.0.1:8000/admin/chat/chat/add/

Django Version: 3.0.4
Python Version: 3.6.5
Installed Applications:
['channels',
'chat',
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'django.contrib.sites',
'allauth',
'allauth.account',
'allauth.socialaccount',
'corsheaders',
'rest_auth',
'rest_auth.registration',
'rest_framework',
'rest_framework.authtoken']
Installed Middleware:
['corsheaders.middleware.CorsMiddleware',
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware']

Template error:
In template E:\Django\Django_Channels\New_Channels\lib\site-packages\django\contrib\admin\templates\admin\includes\fieldset.html, error at line 19
no such table: chat_contact
9 : {% for field in line %}
10 : <div{% if not line.fields|length_is:'1' %} class="fieldBox{% if field.field.name %} field-{{ field.field.name }}{% endif %}{% if not field.is_readonly and field.errors %} errors{% endif %}{% if field.field.is_hidden %} hidden{% endif %}"{% elif field.is_checkbox %} class="checkbox-row"{% endif %}>
11 : {% if not line.fields|length_is:'1' and not field.is_readonly %}{{ field.errors }}{% endif %}
12 : {% if field.is_checkbox %}
13 : {{ field.field }}{{ field.label_tag }}
14 : {% else %}
15 : {{ field.label_tag }}
16 : {% if field.is_readonly %}
17 :

{{ field.contents }}

18 : {% else %}
19 : {{ field.field }}
20 : {% endif %}
21 : {% endif %}
22 : {% if field.field.help_text %}
23 :

{{ field.field.help_text|safe }}

24 : {% endif %}
25 :
26 : {% endfor %}
27 :
28 : {% endfor %}
29 :

Traceback (most recent call last):
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\backends\sqlite3\base.py", line 396, in execute
return Database.Cursor.execute(self, query, params)

The above exception (no such table: chat_contact) was the direct cause of the following exception:
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
response = get_response(request)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\core\handlers\base.py", line 145, in _get_response
response = self.process_exception_by_middleware(e, request)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\core\handlers\base.py", line 143, in _get_response
response = response.render()
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\response.py", line 105, in render
self.content = self.rendered_content
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\response.py", line 83, in rendered_content
return template.render(context, self._request)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\backends\django.py", line 61, in render
return self.template.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 171, in render
return self._render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 163, in _render
return self.nodelist.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 936, in render
bit = node.render_annotated(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\loader_tags.py", line 150, in render
return compiled_parent._render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 163, in _render
return self.nodelist.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 936, in render
bit = node.render_annotated(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\loader_tags.py", line 150, in render
return compiled_parent._render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 163, in _render
return self.nodelist.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 936, in render
bit = node.render_annotated(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\loader_tags.py", line 62, in render
result = block.nodelist.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 936, in render
bit = node.render_annotated(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\loader_tags.py", line 62, in render
result = block.nodelist.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 936, in render
bit = node.render_annotated(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\defaulttags.py", line 209, in render
nodelist.append(node.render_annotated(context))
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\loader_tags.py", line 188, in render
return template.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 173, in render
return self._render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 163, in _render
return self.nodelist.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 936, in render
bit = node.render_annotated(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\defaulttags.py", line 209, in render
nodelist.append(node.render_annotated(context))
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\defaulttags.py", line 209, in render
nodelist.append(node.render_annotated(context))
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\defaulttags.py", line 309, in render
return nodelist.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 936, in render
bit = node.render_annotated(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\defaulttags.py", line 309, in render
return nodelist.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 936, in render
bit = node.render_annotated(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 903, in render_annotated
return self.render(context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 992, in render
return render_value_in_context(output, context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\template\base.py", line 971, in render_value_in_context
value = str(value)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\utils\html.py", line 373, in
klass.str = lambda self: mark_safe(klass_str(self))
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\forms\boundfield.py", line 33, in str
return self.as_widget()
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\forms\boundfield.py", line 96, in as_widget
renderer=self.form.renderer,
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\forms\widgets.py", line 241, in render
context = self.get_context(name, value, attrs)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\contrib\admin\widgets.py", line 288, in get_context
'rendered_widget': self.widget.render(name, value, attrs),
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\forms\widgets.py", line 241, in render
context = self.get_context(name, value, attrs)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\forms\widgets.py", line 678, in get_context
context = super().get_context(name, value, attrs)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\forms\widgets.py", line 639, in get_context
context['widget']['optgroups'] = self.optgroups(name, context['widget']['value'], attrs)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\forms\widgets.py", line 587, in optgroups
for index, (option_value, option_label) in enumerate(self.choices):
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\forms\models.py", line 1140, in iter
for obj in queryset:
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\models\query.py", line 346, in _iterator
yield from self._iterable_class(self, chunked_fetch=use_chunked_fetch, chunk_size=chunk_size)
File "E:\Django\Django_Channels\New_Channels\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 "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\models\sql\compiler.py", line 1151, in execute_sql
cursor.execute(sql, params)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\backends\utils.py", line 100, in execute
return super().execute(sql, params)
File "E:\Django\Django_Channels\New_Channels\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 "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\backends\utils.py", line 77, in _execute_with_wrappers
return executor(sql, params, many, context)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\utils.py", line 90, in exit
raise dj_exc_value.with_traceback(traceback) from exc_value
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\backends\utils.py", line 86, in _execute
return self.cursor.execute(sql, params)
File "E:\Django\Django_Channels\New_Channels\lib\site-packages\django\db\backends\sqlite3\base.py", line 396, in execute
return Database.Cursor.execute(self, query, params)

Exception Type: OperationalError at /admin/chat/chat/add/
Exception Value: no such table: chat_contact

How should I solve this??

[GeonwooVincentKim]

Just delete

db.sqlite3
migrations

and then do it

python manage.py migrate
python manage.py makemigrations your_project_name
python manage.py migrate

again.

And then
Make sure you have to do

python manage.py createsuperuser