Problems adding SlugField field type (Django 1.6.3)

Question

I want share with you this case:

I have the models Albums, Artists, and Tracks

• One Artist may have many Albums
• One Album may have many Tracks
• Many Tracks are inside One Album (may be ManyToMany too ..)

In the Albums Model I want add a field of type SlugField. This is the following:

from django.db import models
from artists.models import Artists

    class Album(models.Model):
        title = models.CharField(max_length=255)
        cover = models.ImageField(upload_to='albums') 
        slug = models.SlugField(max_length=100)
        artist = models.ForeignKey(Artists)

        def __unicode__(self):
            return self.title

I perform the migratios with south:

(myvenv)➜  myvenv  ./manage.py syncdb

Syncing...
Creating tables ...
Installing custom SQL ...
Installing indexes ...
Installed 0 object(s) from 0 fixture(s)

Synced:
> django.contrib.admin
> django.contrib.auth
> django.contrib.contenttypes
> django.contrib.sessions
> django.contrib.messages
> django.contrib.staticfiles
> south
> albums

Not synced (use migrations):
- django_extensions
- djcelery
- tracks
- artists
- userprofiles
(use ./manage.py migrate to migrate these)

(myenv)➜  myenv  ./manage.py convert_to_south albums

Creating migrations directory at '/home/bgarcial/workspace/myenv/sfotipy/albums/migrations'...
Creating __init__.py in '/home/bgarcial/workspace/myenv/sfotipy/albums/migrations'...
+ Added model albums.Album
Created 0001_initial.py. You can now apply this migration with: ./manage.py migrate albums
- Soft matched migration 0001 to 0001_initial.
Running migrations for albums:
- Nothing to migrate.
- Loading initial data for albums.
Installed 0 object(s) from 0 fixture(s)

App 'albums' converted. Note that South assumed the application's models matched the   database
(i.e. you haven't changed it since last syncdb); if you have, you should delete  the  albums/migrations directory, revert models.py so it matches the database, and try again.

(myenv)➜  myenv  ./manage.py migrate albums         

Running migrations for albums:
- Nothing to migrate.
- Loading initial data for albums.
Installed 0 object(s) from 0 fixture(s) 

If I enter the command ./manage.py sqlall, the albums model already appear with the slug field at database

(Sfoti.py)➜  sfotipy  ./manage.py sqlall albums
BEGIN;
CREATE TABLE "albums_album" (
    "id" integer NOT NULL PRIMARY KEY,
    "title" varchar(255) NOT NULL,
    "cover" varchar(100) NOT NULL,
    "slug" varchar(100) NOT NULL,
    "artist_id" integer NOT NULL REFERENCES "artists_artists" ("id")
);
CREATE INDEX "albums_album_f52cfca0" ON "albums_album" ("slug");
CREATE INDEX "albums_album_7904f807" ON "albums_album" ("artist_id");
COMMIT; 

But, When I go to the database, directly to the database structure that Django bring me, I see that the slug field is not effective... This can detail them in this url https://cldup.com/-F9SQ2D3W8.jpeg

With the order to test that this slug works I create the url "albums" which point to the AlbumListView class based view

from django.conf.urls import patterns, url
from artists.views import AlbumListView

urlpatterns = patterns('',
    url(r'^albums/$', AlbumListView.as_view(), name='album_list'),
    url(r'^albums/(?P<artist>[\w\-]+)/$', AlbumListView.as_view(), name='album_list'),
)

The class based view AlbumListView is the following: Here I define a queryset for recovery the albums of an artist and with the kwargs variable is the way in how take

class AlbumListView(ListView):
    model = Album
    template_name = 'album_list.html'

    def get_queryset(self):
        if self.kwargs.get('artist'):
            queryset = self.model.objects.filter(artist__slug=self.kwargs['artist'])
        else:
            queryset = super(AlbumListView, self).get_queryset()
        return queryset

When I go to the view /albums in my browser, I see this message:

no such column: albums_album.slug

This is the image of error in my browser, Check out this url please:

What can be my problem? Why the migration doesn't works? Thanks for your orientation :)

Answer 1

Looks like you added slug to model AFTER run syncdb and BEFORE run convert_to_south. Specifically about your case south's developer displays a warning message in the console:

Note that South assumed the application's models matched the database(i.e. you haven't changed it since last syncdb); if you have, you should delete the albums/migrations directory, revert models.py so it matches the database, and try again.

For fixing your problem, you should:

• Drop SlugField from Album (looks in your console output you should drop artist too)
• Drop migrations folder from albums app
• Run ./manage.py convert_to_south albums
• Run ./manage.py migrate albums
• Add SlugField
• Run ./manage.py schemamigration albums --auto(Specify default value as '')
• Run ./manage.py migrate albums
• Profit!