How to solve an admin operational problem in django?

Question

i am working on an django project (website) i started coding 2 months ago and while working with django project i stucked at a problem.

Actually, I am learning how to make websites, And when i login to admin it works fine but when i add product then it shows

[OperationalError at /admin/products/product/add/
no such table: main.auth_user__old
Request Method: POST
Request URL:    http://127.0.0.1:8000/admin/products/product/add/
Django Version: 3.0.6
Exception Type: OperationalError
Exception Value:    
no such table: main.auth_user__old
Exception Location: C:\Users\Owner\PycharmProjects\Pyshop\venv\lib\site-packages\django\db\backends\sqlite3\base.py in execute, line 396
Python Executable:  C:\Users\Owner\PycharmProjects\Pyshop\venv\Scripts\python.exe
Python Version: 3.8.2
Python Path:    
['C:\\Users\\Owner\\PycharmProjects\\Pyshop',
 'C:\\Users\\Owner\\AppData\\Local\\Programs\\Python\\Python38-32\\python38.zip',
 'C:\\Users\\Owner\\AppData\\Local\\Programs\\Python\\Python38-32\\DLLs',
 'C:\\Users\\Owner\\AppData\\Local\\Programs\\Python\\Python38-32\\lib',
 'C:\\Users\\Owner\\AppData\\Local\\Programs\\Python\\Python38-32',
 'C:\\Users\\Owner\\PycharmProjects\\Pyshop\\venv',
 'C:\\Users\\Owner\\PycharmProjects\\Pyshop\\venv\\lib\\site-packages']
Server time:    Wed, 27 May 2020 04:31:07 +0000][1]

Please help me with this

here are those files

models.py:

from django.db import models


class Product(models.Model):
name = models.CharField(max_length=255)
price = models.FloatField()
stock = models.IntegerField()
image_url = models.CharField(max_length=2083)


class Offer(models.Model):
code = models.CharField(max_length=10)
description = models.CharField(max_length=255)
discount = models.FloatField(5)

views.py:

from django.http import HttpResponse
from django.shortcuts import render


def index(request):
return HttpResponse('Hello world')


def new(request):
return HttpResponse('New Products!!!!!!!!!!!!!')


def microsoft(request):
return HttpResponse('microsoft 365')

project urls.py:

"""pyshop URL Configuration

The `urlpatterns` list routes URLs to views. For more information please see:
https://docs.djangoproject.com/en/2.1/topics/http/urls/
Examples:
Function views
1. Add an import:  from my_app import views
2. Add a URL to urlpatterns:  path('', views.home, name='home')
Class-based views
1. Add an import:  from other_app.views import Home
2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
Including another URLconf
1. Import the include() function: from django.urls import include, path
2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
"""
from django.contrib import admin
from django.urls import path, include

urlpatterns = [
path('admin/', admin.site.urls),
path('product/', include('product.urls'))
]

product.url.py:

from django.urls import path
from . import views


urlpatterns = [
path('', views.index),
path('new/', views.new),
path('microsoft/', views.microsoft)
]

here are those views, models. urls files please solve the problem !!!!

Answer 1

First check if you have syn your database i.e. by running

python manage.py makemigrations
python manage.py migrate

If this shows some error or doesn't work then try deleting all migration files and __pychache__ except __init__.py and run makemigrations and migrate commands again.

Answer 2

all you have to do is to migrate after creating the models in models.py steps:

1. create the models in models.py

2. go to cmd and go to the path of your project ( the place where you run the server)

3)type the command :python manage.py migrate

4)click enter

4)then type : python manage.py makemigrations

5)in the place of put the name of your app after that click enter

6)type the command :python manage.py migrate

that's all and the problem is solved