FOREIGN KEY约束失败，为什么出现此错误？

编程问答 2022-09-17

问题描述

我正在创建一个博客，现在我在注释部分中工作，在编辑注释中工作，一切正常，但是问题出在下面，每当​​我更新要重定向的视图时我对博客文章发表了评论，但是每当我这样做时，都会收到标题中的错误，这是代码：@H_404_1@

models.py @H_404_1@

在这里，我想以与在Post Model中相同的方式进行重定向，该模型将重定向到文章详细信息@H_404_1@ 

class Post(models.Model):
    title = models.CharField(max_length= 255)
    header_image = models.ImageField(null = True,blank = True,upload_to = 'images/')
    author = models.ForeignKey(User,on_delete=models.CASCADE)
    body = RichTextField(blank = True,null = True)
    #body = models.TextField()
    post_date = models.DateField(auto_Now_add=True)
    category = models.CharField(max_length=255,default='coding')
    snippet = models.CharField(max_length=255)
    likes = models.ManyToManyField(User,related_name = 'blog_posts')

    def total_likes(self):
        return self.likes.count()

    def __str__(self):
        return self.title + ' | ' + str(self.author)
    
    def get_absolute_url(self):
        return reverse('app1:article-detail',args=(self.id,))

class Comment(models.Model):
    
    post = models.ForeignKey(Post,related_name="comments",on_delete=models.CASCADE)
    name = models.ForeignKey(User,on_delete=models.CASCADE)
    body = models.TextField()
    date_added = models.DateTimeField(auto_Now_add=True)

    def __str__(self):
        return '%s - %s' % (self.post.title,self.name)

    def get_absolute_url(self):
        return reverse('app1:article-detail',))

views.py @H_404_1@

在这两个视图中，是否要重定向到存储所有评论的文章详细信息，这与发布相同，但它显示了一个错误@H_404_1@ 


class AddCommentView(CreateView):
    model = Comment
    form_class = CommentForm
    template_name = 'app1/add_comment.html'
    def form_valid(self,form):
        form.instance.post_id = self.kwargs['pk']
        form.instance.name = self.request.user
        return super().form_valid(form)
    #fields = '__all__'
    success_url = reverse_lazy('index')

class UpdateCommentView(UpdateView):
    model = Comment
    template_name = 'app1/update_comment.html'
    form_class = CommentForm

    def form_valid(self,form):
        form.instance.post_id = self.kwargs['pk']
        form.instance.name = self.request.user
        return super().form_valid(form)

回溯@H_404_1@ 

Traceback (most recent call last):
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\backends\utils.py",line 86,in _execute
    return self.cursor.execute(sql,params)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\backends\sqlite3\base.py",line 396,in execute
    return Database.Cursor.execute(self,query,params)
sqlite3.IntegrityError: FOREIGN KEY constraint Failed

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\core\handlers\exception.py",line 34,in inner
    response = get_response(request)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\core\handlers\base.py",line 115,in _get_response
    response = self.process_exception_by_middleware(e,request)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\core\handlers\base.py",line 113,in _get_response
    response = wrapped_callback(request,*callback_args,**callback_kwargs)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\views\generic\base.py",line 71,in view
    return self.dispatch(request,*args,**kwargs)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\views\generic\base.py",line 97,in dispatch
    return handler(request,**kwargs)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\views\generic\edit.py",line 194,in post
    return super().post(request,line 142,in post
    return self.form_valid(form)
  File "C:\Users\snin2\Desktop\basura\lapagina\app1\views.py",line 24,in form_valid
    return super().form_valid(form)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\views\generic\edit.py",line 125,in form_valid
    self.object = form.save()
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\forms\models.py",line 459,in save
    self.instance.save()
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\models\base.py",line 745,in save
    self.save_base(using=using,force_insert=force_insert,File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\models\base.py",line 782,in save_base
    updated = self._save_table(
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\models\base.py",line 864,in _save_table
    updated = self._do_update(base_qs,using,pk_val,values,update_fields,line 917,in _do_update
    return filtered._update(values) > 0
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\models\query.py",line 771,in _update
    return query.get_compiler(self.db).execute_sql(CURSOR)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\models\sql\compiler.py",line 1492,in execute_sql
    cursor = super().execute_sql(result_type)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\models\sql\compiler.py",line 1144,in execute_sql
    cursor.execute(sql,params)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\backends\utils.py",line 100,in execute
    return super().execute(sql,line 68,in execute
    return self._execute_with_wrappers(sql,params,many=False,executor=self._execute)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\backends\utils.py",line 77,in _execute_with_wrappers
    return executor(sql,many,context)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\backends\utils.py",params)
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\utils.py",line 90,in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "C:\Users\snin2\anaconda3\envs\MyDjangoEnv\lib\site-packages\django\db\backends\utils.py",params)
django.db.utils.IntegrityError: FOREIGN KEY constraint Failed
[10/Aug/2020 16:15:21] "POST /app1/update_comment/10 HTTP/1.1" 500 179169

解决方法

如果您直接从数据库或管理站点中删除了任何信息，则那里可能会发生错误。

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