Import csv file using django - Exception Type: DatabaseError

Question

I am trying to create a django project and I need to upload a csv file and create objects.

I found a video: https://www.youtube.com/watch?v=t3BdM6JlAmY and https://simpleisbetterthancomplex.com/tutorial/2016/08/01/how-to-upload-files-with-django.html.

My code: sales/model.py

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

# Create your models here.
class Sales(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    date = models.CharField(max_length=10, blank=False, null= False)
    product = models.CharField(max_length=10, blank=False, null= False)

    def __str__(self):
        return f"{self.user}"

sales/admin.py

from django.contrib import admin
from .models import Sales

admin.site.register(Sales)

In the main project, settings, I added that part about Media.

urls.py

from django.contrib import admin
from django.urls import path, include
from django.conf import settings
from django.conf.urls.static import static

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

urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

csvs/models.py

from django.db import models
class Csv(models.Model):
    file_name = models.FileField(upload_to='csvs')
    uploaded = models.DateTimeField(auto_now_add = True)
    activated = models.BooleanField(default= False)

    def __str__(self):
        return f"File id: {self.id}"

csvs/forms.py

from django import forms
from .models import Csv

class CsvModelForm(forms.ModelForm):
    class Meta:
        model = Csv
        fields =('file_name',)

and views.py

from django.shortcuts import render
from .forms import CsvModelForm
from .models import Csv
import csv
from django.contrib.auth.models import User
from sales.models import Sales

def upload_file_view(request):
        form = CsvModelForm(request.POST, request.FILES)
        if form.is_valid():
            form.save()
            form = CsvModelForm()

            obj= Csv.objects.get(activated=False)
            with open(obj.file_name.path, 'r') as f:
                reader = csv.reader(f)

                for i, row in enumerate(reader):
                    if i==0: 
                        pass
                    else: 
                        #row = "".join(row)
                        #row = row.replace(";"," ")
                        #row=row.split()

                        #print(row)
                        #print(type(row))
                        date = row[1]
                        user = User.objects.get(username=row[0])
                        Sales.objects.create(
                            date=date,
                            product= row[2],
                            user=user,
                        )
                obj.activated=True
                obj.save()
        return render(request, 'upload.html', {
        'form': form
    })

The error that I have after I upload the file is "Exception Type: DatabaseError". If I scroll more down, I see that I have an exception on this line.

I want to mention that I am working with the mongodb. If I try all the code for sqlite3 data base, all is good and I don't have any problem.

And I tried to delete all the migrations and do the steps with makemigrations, migrate, create superuser, but nothing happened.

Thanks for your time!