Question

I’m following a Django book (Django 1.0 Web Site Development). I’m finding that the book, although straight forward and easy to read, leaves out small details. However, this error that I’m getting, I have not been able to find a solution online. Thanks for any help.

Below, I added the Tag class to my models.py file.

from django.db import models
from django.contrib.auth.models import User


class Link(models.Model):
    url = models.URLField(unique=True)



class Bookmark(models.Model):
    title = models.CharField(max_length=200)
    user = models.ForeignKey(User)
    link = models.ForeignKey(Link)



class Tag(models.Model):
    name = models.CharField(max_length=64, unique=True)
    bookmarks = models.ManyToManyField(Bookmark)

Then I attempt to run the following code at the python shell:

from bookmarks.models.import *
bookmark = Bookmark.objects.get(id=1)

As a result, I get the following error:

Traceback (most recent call last):
File "(console)", line 1, in (module)
File "c:\Python27\lib\site\-packages\django\db\models\manager.py", line 132, in get
   return self.get_query_set().get(*args, **kwargs)
File "c:\Python27\lib\site-packages\django\db\models\query.py", line 349, in get
   % self.model._meta.object_name)
DoesNotExist: Bookmark matching query does not exist.

Answer 1

The error means just what it says. DoesNotExist is raised by QuerySet.get() if there is no object in the database that would match the conditions given to the QuerySet. In this case it means there is no Bookmark object in the database with an ID equal to 1.