Question

I’m in new territory with Django/Python. I’m building a site where the user selects from a list of available services, and then enters info about the services.

I didn’t want to keep the service list in the database, becasue that’s really more site configuration info rather than user info. So I’m setting them as an Object Class (recommended by a friend)

class Service(object):
    def __init__(self, name, sections, link,  enabled=True):
        self.name = name
        self.link = link
        self.sections = sections
        self.enabled = enabled

SERVICES = {
    'SERVICE1': ArtistService(
        'Service Name',
        ['Section Name 1','Section Name 2',],
        'http://www.service.com',
    ),

Is it possible to use this class as a foreign key in the database? I’d like to retreive some information about the service from the class though a template join. Example:

{% for s in user_activated_services %}
    {{ s.service.name }}    
{% endfor %}

But it’s not working because I’m just saving the key in a CharField in the user_activated_services model:

class ActivatedServices(models.Model):
    user_page = models.ForeignKey(Page)
    service = models.CharField(max_length=20, choices=[(k, s.name) for k, s in userservices.services.SERVICES.iteritems()])

When I try to replace with a foreign key, I get an error of “First parameter to ForeignKey must be either a model, a model name, or the string ‘self'”

Anyway, I think I know the problem, I just can’t fix it. Hope this is enough info. I’m sure I’m missing something stupid.

Thanks in advance.

Answer 1

Is it possible to use this class as a foreign key in the database?

No.

Only models.Model classes can be used as foreign keys.

“Foreign Key” is a database concept.

If you want to have non-database things as foreign keys, they’re just strings or numbers and the “reference” is a simple mapping that you manage in your code.