如何在部署系统时向特定的系统发送多个通知？

Question

我试图向特定的用户发送通知。它可以在我的本地主机上工作，我可以向用户发送任意数量的通知，但是当我试图部署它时，我只能向特定用户发送一个通知。当我试图再次向同一个用户发送通知时，我会看到一个错误，即

重复键值违反唯一约束"user_notifications_usernotification_sender_id_key“和DETAIL: key (sender_id)=(1)已经存在。我使用heroku部署我的系统和Postgresql作为我的数据库。

我已经尝试将我的发件人关系从OneToOneField更改为Foreignkey，但是仍然会遇到相同的错误。

python models.py

class UserNotification(models.Model):
    sender= models.OneToOneField(User,on_delete=models.CASCADE,related_name='user_sender',unique=True)
    receiver= models.ForeignKey(User,on_delete=models.CASCADE,related_name='user_receiver',unique=False)
    concern_type= models.CharField(max_length=100,choices=CHOICES)
    content = models.TextField(max_length=255,blank=False)
    date_sent= models.DateTimeField(default = timezone.now)

views.py

def send_notifications(request):# form that admin can send notification to a specific user.
    if request.method == 'POST':
        form = SendNotificationForm(request.POST)
        if form.is_valid():
            instance = form.save(commit=False)
            instance.sender = request.user
            receiver = instance.receiver
            instance.save()
            messages.success(request,'Your notification was sent successfully!')
            return redirect('send-notification-form')
    else:
        form = SendNotificationForm()
    template_name = ['user-forms/send-notification-form.html']
    context = {'form':form}
    return render(request,template_name,context)
def user_notifications(request): # notification module of users
    notifications   = UserNotification.objects.filter(receiver__exact=request
        .user).order_by('-date_sent')
    context = { 'notifications':notifications }
    template_name = ['notification.html']
    return render(request,template_name,context)

forms.py

class SendNotificationForm(forms.ModelForm):
    class Meta:
        model = UserNotification
        fields = ['receiver','concern_type','content']

Answer 1

我刚解决了我的错误。我只是重置我的数据库，然后用heroku命令迁移它。