django-mptt

Here is the situation. I'm utilizing an MPTT Model in Django to create a hierarchy of music genres (Rock, Hard Rock, etc). I'm assigning one of the nodes of this hierarchy to an Album. Let's say I create a Album object with Hard Rock genre. How can I query my Albums for all Rock albums and have it include Rock and all descendants of the Rock genre? class Genre(MPTTModel): name = models.CharField(max_length=50, unique=True) parent = TreeForeignKey('self', null=True, blank=True, related_name='children') class MPTTMeta: order_insertion_by = ['name'] def __unicode__(self): return self.name class

In an online shop I use django-mptt for product categories with several levels. I also have products that each belong to a category. Now I'd like to visualise the category tree like this: all(18) - edible (10) -- food (4) -- drink (6) - inedible (8) -- wood (3) -- rock (5) where the numbers in scopes are the product counts for each category. I am able to visualize the category tree. I can also place the product count behind the category names, but the way I am doing it seems very inefficient. I basically have a get_number_of_products() methods at the category model which returns the number of

I am developing a website that requires tagging up different types of content, which favors using django-taggit. But, it would be extremely beneficial if the tags were represented in the database in their natural hierarchy, favoring use of django-mptt or django-treebeard. What is the best solution to integrate the generic tagging functionality of taggit with the tree-structure provided by mptt / treebeard? Tentacles I used treebeard and taggit's custom through models to implement hierarchical tags. Just found this yesterday, so I can't really tell if it's what you're looking for: django

Imagine that I have an mptt tree of objects and their population like: Animal, 60 aardvark, 30 bobcat, 20 chipmunk, 10 Vegetable, 6 apple, 1 beet, 2 cauliflower, 3 Mineral 0 How would you sort the above by population on each sublevel? I want to get to: Animal, 60 aardvark, 30 bobcat, 20 chipmunk, 10 Vegetable, 6 cauliflower, 3 beet, 2 apple, 1 Mineral 0 I am building off of mptt in django. affan I've just solved a similar issue. You can use an order_by , but not simply by the field you want to sort by: MyModel.tree.all().order_by('tree_id', 'level', 'your_sort_field') Try to add it in the

Does anybody have an efficient algorithm to retrieve all ancestors of an mptt queryset? The best I could think of so far is something like this: def qs_ancestors(queryset): if isinstance(queryset, EmptyQuerySet): return queryset queryset_aggs = queryset.values_list('tree_id', 'level').annotate(max_lft=Max('lft'), min_rght=Min('rght')) new_queryset = queryset.none() for tree_id, level, max_lft, min_rght in queryset_aggs: ancestors = MyModel.objects.filter( tree_id=tree_id, level__lt=level, lft__lte=max_lft, rght__gte=min_rght, ) new_queryset = ancestors | new_queryset return new_queryset There