NOT NULL constraint failed: shop_review.item_id

def order(request, item_id):
item = get_object_or_404(Item, pk=item_id)
if request.method == "POST":
    username = None
    username = request.user.username
    userInfo = username + '/' + request.POST["nameNum"]
    userAddr = request.POST["address"]
    new_order = Review.objects.create(
        reviewText = userInfo,
        votes = userAddr
    )
    return HttpResponse("<script>alert('" + userInfo + '/ ' + userAddr + "');</script> 등록 완료")
return render(request, 'order.html', {'item': item})

This is my views.py, and

class Item(models.Model):
def __str___(self):
    return self.item_name
item_name = models.CharField(max_length=100)
item_text = models.CharField(max_length=300)
pub_date = models.DateTimeField('date published')
item_amount = models.CharField(max_length=99999999)
item_image = models.ImageField(upload_to='image/', blank=True)
item_id = models.AutoField(primary_key=True)

this is my models.py.

And when I run this part, NOT NULL constraint failed: shop_review.item_id << this error occurs. How can I fix this error?

enter image description here