Why am I getting this error? UNIQUE constraint failed: app1_comment.user_id

Question

The thing is that I'm creating a comment section for my post, and I want to add an edit button for each comment created by the user, but the thing is that I can only add one comment per user or I get the error in the title, and I'm not sure how to fix this, so here's the code

models.py

class Category(models.Model):
    name = models.CharField(max_length= 255)
    
    def __str__(self):
        return self.name 
    
    def get_absolute_url(self):
        return reverse('index')

class Profile(models.Model):
    user = models.OneToOneField(User, null = True, on_delete=models.CASCADE)
    bio = models.TextField()
    profile_pic = models.ImageField(null = True, blank = True, upload_to = "images/profile/")
    website_url = models.CharField(max_length= 255, blank = True, null = True)
    facebook_url = models.CharField(max_length= 255, blank = True, null = True)
    twitter_url = models.CharField(max_length= 255, blank = True, null = True)
    instagram_url = models.CharField(max_length= 255, blank = True, null = True)
    pinterest_url = models.CharField(max_length= 255, blank = True, null = True)

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

    def get_absolute_url(self):
        return reverse('index')
        
    

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):
    user = models.OneToOneField(User, null = True, on_delete=models.CASCADE)
    post = models.ForeignKey(Post, related_name="comments", on_delete=models.CASCADE)
    name = models.CharField(max_length=255)
    body = models.TextField()
    date_added = models.DateTimeField(auto_now_add=True)

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

views.py

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.user = self.request.user
        return super().form_valid(form)


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.user = self.request.user
        return super().form_valid(form)
    #fields = '__all__'
    success_url = reverse_lazy('index')

template

<div class="container">
<h1>Post</h1>
{% for post in object_list %}
    <li><a href="{% url 'app1:article-detail' post.pk %}">{{post.title}}</a> -
    {{post.author}} - <small>{{post.post_date}}</small> - <small> category : <a href="{% url 'app1:category' post.category|slugify %}">{{post.category}}</a> - </small>
    {% if user.is_authenticated %}
    {% if user.id == post.author.id %}
    <small><a href="{% url 'app1:updatepost' post.pk %}">Edit</a></small><small>
    <a href="{% url 'app1:deletepost' post.pk %}">- Delete</a>  
    </small></li>
    {{post.snippet}}
    {% endif %}
    {% endif %}

Answer 1

Your comment model must be a Foreignkey not a OneToOneField:

class Comment(models.Model):
    user = models.ForeignKey(User, null = True, on_delete=models.CASCADE)
...