Django："NOT NULL constraint failed: users_investment.user_id" 错误

Question

我正在做一个项目，我希望许多用户注册许多 offered_funds，所以我添加了一个 ManyToManyField。我还希望 Django 自动找出哪个用户登录并自动填写用户字段，所以我将其写在我的 views.py 文件中。然而，在这样做时，我遇到了错误：

NOT NULL constraint failed: users_investment.user_id

这是我的 models.py:

# Not sure if this class is relevant to my question
class UserProfile(models.Model):
    user = models.OneToOneField(User)
    first_name = models.CharField(max_length=24)
    last_name = models.CharField(max_length=24)
    phone_number = models.CharField(max_length=12)
    account_type = models.CharField(max_length=55, choices=ACCOUNT_TYPES)

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

class Investment(models.Model):
    user = models.ManyToManyField(User, blank=True)
    offered_fund = models.ForeignKey(OfferedFunds)
    amount = models.IntegerField(default=0)
    purchase_date = models.DateTimeField(auto_now_add=True)

    def __int__(self):
        return self.offered_fund.fund_name.name

我的forms.py:

class InvestmentForm(forms.ModelForm):
    class Meta:
        model = Investment
        fields = ('offered_fund','amount')
        exclude = ['user']

最后，我的 views.py:

def of_details(request, slug):
    context_dict = {}

    of = get_object_or_404(OfferedFunds, slug=slug)
    context_dict['of'] = of

    default_state = OfferedFunds.objects.get(slug=slug)
    form = InvestmentForm(request.POST or None, initial={'offered_fund': default_state})

    if form.is_valid():
        instance = form.save(commit=False)
        #instance.user = request.user
        instance.offered_fund = default_state
        instance.save()
        instance.user.add(request.user) # Where the problem started
    context_dict['form'] = form

    return render(request, 'funds/offered-funds-details.html', context_dict)

在我的 views.py 中，我评论了导致此问题的代码 issue.I 无法想象为什么 Django 会因为用户字段有值（非空）而生气。有人对我如何解决这个问题有任何想法吗？我没有 python manage.py flush 来清除我的数据库，但仍然没有成功。谢谢

Answer 1

我认为您的问题是您收到的是 anonymous user object 而不是经过完全身份验证的用户（如果经过身份验证的用户未登录，Django 将自动使用匿名用户填充 request.user。匿名用户的 id 始终是 None - 因此数据库约束失败。

您需要首先检查是否 request.user.is_authenticated() 来确保您的用户不是匿名的：

if request.user.is_authenticated():
    instance.user.add(request.user)

Django："NOT NULL constraint failed: users_investment.user_id" 错误

Django: "NOT NULL constraint failed: users_investment.user_id" Error

python

django

django-models

django-forms

django-views