Adding List to Object in Django View

Question

I have searched and read through the internet trying to figure out this problem. Thank you for any advice on this issue.

I have been having problems adding a list of objects to another object in Django. I have an object 'category' and a list of objects 'subcategory', but when I try to put them together as a package 'ad', there is a TypeError: 'subcategory' is an invalid keyword argument for this function.

Here is the view:

def create_in_category(request, slug):
   category = get_object_or_404(Category, slug=slug)
   subcategory = SubCategory.objects.all()

   ad = Ad.objects.create(category=category, subcategory=subcategory, user=request.user,
                       expires_on=datetime.datetime.now(), active=False)
   ad.save()

What am I missing to be able to get all of these elements together? Thanks very much for sharing your knowledge.

Edit: added the models.

class Category(models.Model):
   name = models.CharField(max_length=200)
   slug = models.SlugField()

   def __unicode__(self):
       return self.name + u' Category'

class SubCategory(models.Model):
   name = models.CharField(max_length=50, unique=True)
   category = models.ManyToManyField(Category)

   def __unicode__(self):
       return self.name + u' SubCategory'

Post your models. How are we supposed to help if we don't even know how your code works? — Chris Pratt
– Chris Pratt, Commented Jul 6, 2012 at 17:32
Nick, edit your answer and include the code from your models.py — César
– César, Commented Jul 6, 2012 at 17:47
Sorry for being cryptic. The models are added above. Thanks for your support. — Nick Bewley
– Nick Bewley, Commented Jul 6, 2012 at 20:05
I know you got the answer already, but it may be worth a look at the django project cookbook's examples: code.djangoproject.com/wiki/CookBookCategoryDataModelPostMagic code.djangoproject.com/wiki/ModifiedPreorderTreeTraversal — Francis Yaconiello
– Francis Yaconiello, Commented Jul 7, 2012 at 23:52
Thank you @FrancisYaconiello. I checked out the cookbook link. It is interesting, but not compatible with my version of django (1.3). Also have experimented with mptt. Thanks for the suggestions — Nick Bewley
– Nick Bewley, Commented Jul 9, 2012 at 18:13

Francis Yaconiello · Accepted Answer · 2012-07-06 18:08:01Z

2

i'm not positive what you are doing or why, but just to put my 2 cents in:

If you are going to do categories w/ hierarchy (unless there is something different (aside from position in the hierarchy) maybe you should use something like https://github.com/django-mptt/django-mptt/

class Category(MPTTModel) :
    """initial Category model"""
    title = models.CharField(
        verbose_name    = _(u'Title'), 
        help_text           = _(u'This category.'),
        max_length      = 255
    )
    slug = models.SlugField(
        verbose_name    = _(u'Slug'),
        help_text           = _(u'Unique identifier for this category.'),
        max_length      = 255,
        unique              = True
    )
    parent = models.ForeignKey(
        'self',
        null                            = True, 
        blank                           = True, 
        default                     = None,
        verbose_name            = _(u'Parent Category')
    )

    class MPTTMeta:
        order_insertion_by  = ['title', ]

    class Meta:
        verbose_name                = _(u'Category')
        verbose_name_plural = _(u'Categories')

    def __unicode__(self):
        return '%s' % (self.title,)

then you can use all of the fancy hierarchy building tools that MPTT gives you

answered Jul 6, 2012 at 18:08

Francis Yaconiello

10.9k2 gold badges38 silver badges55 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Nick Bewley Over a year ago

Thank you for elaborating on a method to use django-mptt.

Daniel Roseman · Accepted Answer · 2012-07-06 18:02:00Z

1

Using my crystal ball, I can tell that subcategory is for some reason a ManyToMany relation, and you can't pass that in on instantiation (because it needs a saved instance on both ends before the relationship can be created). Instantiate and save the Ad first, then add the relationship with ad.subcategory.add(*subcategory)

As to whether that relationship should in fact be a ManyToMany at all is another question (what would it mean for a subcategory to be able to belong to multiple categories?).

edited Jul 6, 2012 at 18:02

answered Jul 6, 2012 at 17:53

Daniel Roseman

602k68 gold badges910 silver badges923 bronze badges

1 Comment

César Over a year ago

Damn, where can I get that crystal ball? :)

Collectives™ on Stack Overflow

Adding List to Object in Django View

2 Answers 2

1 Comment

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related