Django script add field to database

I added a slug field to my database and now need to go through and add those. I want to run a script that looks at the slug field in the database and if empty generates and saves. Here is what I thought was along the lines, but is not working.

from project.apps.tracks.models import *

def process_slug():  
    if not track.slug:  
        slug = slugi开发者_如何学运维fy("%s - %s" % (track.name, track.artist)) 
    else:  
        slug = "" 

    super(process_slug, track).save()

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From your posted code it is not evident, that you are actually looping through all your Track objects.

from project.apps.tracks.models import Track
# import for slugify

def process_slug():
    """ Populate slug field, if they are empty. 
    """
    for track in Track.objects.all():
        if not track.slug:  
            slug = slugify("%s - %s" % (track.name, track.artist)) 
            track.slug = slug
            track.save()

One preferred place for such occasionally recurring commands would be under management/commands inside your application.

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Another way to implement would be to override your Track model's save method. It would check for emtpy slugs on every save (which is not performant).

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You can set the default like this:

slug = models.SlugField(default=process_slug)