2. As a storage of several trees of categories, e.g.::
Model 1
Category 1
Subcategory 1-1
Subcategory 1-2
subcategory 1-2-1
Category 2
Subcategory 2-1
Model 2
Category 3
Subcategory 3-1
Subcategory 3-2
subcategory 3-2-1
Category 4
Subcategory 4-1
You can't do it as both at the same time, though.
Connecting your model with Django-Categories
============================================
Because there are a few additional methods and attributes that your model needs, you can't simply create a ``ForeignKey`` to ``Category``, even though that is eventually what happens.
You add a many-to-one or many-to-many relationship with Django Categories using the ``CATEGORIES_SETTINGS['FK_REGISTRY']`` and ``CATEGORIES_SETTINGS['M2M_REGISTRY']`` settings respectively. For more information see :ref:`registering_models`\ .