Python 问题：NOT NULL 约束失败

因此，我目前正在为我的学校项目建立一个在线store .在网上store ，用户应该能够提交对每种产品的 comments .不过，我在提交 comments 时遇到了一些问题.它给了我这个错误:

NOT NULL constraint failed:

我已经被困在这个问题上大约15个小时了，我似乎解决不了它.如果能得到所有的帮助，我将不胜感激.

回溯:

Traceback (most recent call last):
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/backends/utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/backends/sqlite3/base.py", line 423, in execute
    return Database.Cursor.execute(self, query, params)

The above exception (NOT NULL constraint failed: products_reviewrating.user_id) was the direct cause of the following exception:
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/core/handlers/exception.py", line 47, in inner
    response = get_response(request)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/core/handlers/base.py", line 181, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/workspace/webster00/products/views.py", line 91, in submit_review
    newreview.save()
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/models/base.py", line 726, in save
    self.save_base(using=using, force_insert=force_insert,
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/models/base.py", line 763, in save_base
    updated = self._save_table(
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/models/base.py", line 868, in _save_table
    results = self._do_insert(cls._base_manager, using, fields, returning_fields, raw)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/models/base.py", line 906, in _do_insert
    return manager._insert(
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/models/query.py", line 1270, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1410, in execute_sql
    cursor.execute(sql, params)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/backends/utils.py", line 98, in execute
    return super().execute(sql, params)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/backends/utils.py", line 66, in execute
    return self._execute_with_wrappers(sql, params, many=False, executor=self._execute)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/backends/utils.py", line 75, in _execute_with_wrappers
    return executor(sql, params, many, context)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/backends/utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/utils.py", line 90, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/backends/utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)
  File "/workspace/.pip-modules/lib/python3.8/site-packages/django/db/backends/sqlite3/base.py", line 423, in execute
    return Database.Cursor.execute(self, query, params)

Exception Type: IntegrityError at /products/submit_review/6/
Exception Value: NOT NULL constraint failed: products_reviewrating.user_id

Views.py

def submit_review(request, product_id):
    print(f'product_id: {product_id}')
    url = request.META.get('HTTP_REFERER')
    if request.method == 'POST':
        try:
            product = Product.objects.get(id=product_id)
            reviews = ReviewRating.objects.filter(user=request.user.userprofile, product=product).first()
            form = ReviewForm(request.POST, instance=reviews)
            newreview = form.save(commit=False)
            newreview.product = product
            newreview.save()
            form.save()

            messages.success(request, 'Thank you! Your review has been updated')
            return redirect(url)
        except ReviewRating.DoesNotExist:
            form = ReviewForm(request.POST)
            if form.is_valid():
                data = ReviewRating()
                data.subject = form.cleaned_data['subject']
                data.rating = form.cleaned_data['rating']
                data.review = form.cleaned_data['review']
                data.ip = request.META.get('REMOTE_ADDR')
                data.product_id = product_id
                data.user_id = request.user.id
                data.save()
                messages.success(request, 'Thank you! Your review has been submited.')
                return redirect(url)

comments 也没有在Django管理员中显示.