Database Error - no such column - django

Question

I have a project, with an app, article. And there I have a page to list all the articles, and another to display the selected article and its comments. Everything was fine before I used migration from south, and made some changes, i.e., before in the Comment model i had a field for
name = models.CharField(max_length=200)
and changed it to:
first_name = models.CharField(max_length=200)
second_name = models.CharField(max_length=200)
Now when i load my articles.html page, everthings ok, but when i load article.html, i get an error:
DatabaseError at /articles/get/1/
no such column: article_comment.first_name
Error during template rendering
In template C:\Users\Robin\web\django_test\article\templates\article.html, error at line 21
In in line 21 article.html:
{% if article.comment_set.all %}
I think the problem is with comment_set.all. Even in the console it gives me the same error as the above. So, how do i get all the comments from the given aritcle? Or did I made some mistake in the code? Any help will be greatly appreciated. Thank you.
Models.py:
from django.db import models
from time import time
def get_upload_file_name(instance, filename):
return "uploaded_files/%s_%s" % (str(time()).replace('.','_'), filename)
class Article(models.Model):
title = models.CharField(max_length=200)
body = models.TextField()
pub_date = models.DateTimeField('date published')
likes = models.IntegerField(default=0)
thumbnail = models.FileField(upload_to=get_upload_file_name)
def __unicode__(self):
return self.title
class Comment(models.Model):
first_name = models.CharField(max_length=200)
second_name = models.CharField(max_length=200)
body = models.TextField()
pub_date = models.DateTimeField('date published')
article = models.ForeignKey(Article)
views.py:
def article(request, article_id=1):
return render_to_response('article.html',
{'article': Article.objects.get(id=article_id) })
forms.py:
class CommentForm(forms.ModelForm):
class Meta:
model = Comment
fields = ('first_name','second_name', 'body')
article.html:
{% extends "base.html" %}
{% block sidebar %}
<ul>
<li>Articles</li>
</ul>
{% endblock %}
{% block content%}
<h1>{{article.title}}</h1>
<p>{{article.body}}</p>
{% if article.thumbnail %}
<p><img src="/static/assets/{{ article.thumbnail }}" width="200"/></p>
{% endif %}
<p>{{ article.likes }} people liked this article.</p>
<p>Like</p>
<h2>Comments</h2>
{% if article.comment_set.all %}
{% for c in article.comment_set.all %}
<p>{{ c.name }}: {{ c.body }}</p>
{% endfor %}
{% else %}
<p>No comment</p>
{% endif %}
<p>Add comment</p>
{% endblock %}