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'

Answer 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?).