CODEWITHSUNDEEP
pythondjangoview
Nick Bewley
Nick Bewley

Reputation: 9289

Adding List to Object in Django View

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'

Upvotes: 0

Views: 530

Answers (2)

Francis Yaconiello
Francis Yaconiello

Reputation: 10919

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

Upvotes: 2

Daniel Roseman
Daniel Roseman

Reputation: 599610

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?).

Upvotes: 1

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