CODEWITHSUNDEEP
pythondjango
Sefa
Sefa

Reputation: 8992

Django - NameError: name 'Post' is not defined in many to many relationship

I'm very new to Python and Django. I'm trying to create a basic blog engine containing categories, posts and tags.

A category will have multiple posts

A post will have multiple tags

So i designed my models like this:

from django.db import models

class Category(models.Model):
    category_name = models.CharField(max_length=200)
    posts = models.ManyToManyField(Post)

    def __str__(self):              
        return self.category_name

class Post(models.Model):
    post_title = models.CharField(max_length=200)
    post_body = models.TextField()
    post_tags = models.ManyToManyField(Tag)

    def __str__(self):
        return self.post_title

class Tag(models.Model):
    tag_title = models.CharField(max_length=200)

    def __str__(self):
        return self.tag_title

When i run python manage.py migrate command, i am getting 

File "/Development/Projects/pBlog/blogEngine/models.py", line 6, in Category
    posts = models.ManyToManyField(Post)
NameError: name 'Post' is not defined

Error. Is there any syntax error? I have .Net background i might need to change my whole approach.

Upvotes: 3

Views: 2592

Answers (2)

dryeel
dryeel

Reputation: 3

The problem is that you have defined class Category before you defined class Post - and you are calling Post id from Category. just cut it out (class Category), and paste it under class Post

Upvotes: 0

garnertb
garnertb

Reputation: 9594

The Post class is not yet defined when you refer to it on line 6. In this situation, you should use the name of the model instead:

class Category(models.Model):
    category_name = models.CharField(max_length=200)
    posts = models.ManyToManyField("Post")

    def __str__(self):              
        return self.category_name

This is documented here: https://docs.djangoproject.com/en/1.7/ref/models/fields/#django.db.models.ForeignKey.

Upvotes: 6

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