How to count and display objects in relation ManyToMany in Django

Question

I have a simple model with news and categories:

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

class News(models.         


        

Answer 1

Very simple:

>>> for category in Category.objects.all():
...     print category.name, category.news_set.count()

Answer 2

Check out annotate() function from Django 1.1.

http://docs.djangoproject.com/en/dev/topics/db/aggregation/#topics-db-aggregation

Example (from that URL above):

>>> q = Book.objects.annotate(num_authors=Count('authors'))
>>> q[0].num_authors
2
>>> q[1].num_authors
1