is a generic drag-and-drop ordering package to sort objects in the list- and detail inline-views of the Django admin interface. This package offers simple mixin classes which enriches the functionality of any existing class derived from admin.ModelAdmin, admin.StackedInline or admin.TabularInline. It thus makes it very easy to integrate with existing models and their model admin interfaces.

Project home:

django-admin-sortable2 demo

Why another adminsortable plugin?

All available plugins which add functionality to make list views for the Django admin interface sortable, offer a base class to be used instead of models.Model. This abstract base class then contains a hard coded position field, additional methods, and meta directives. The problem with such an approach is twofold:

First, an is-a relationship is abused to enrich the functionality of a class. This is bad OOP practice. A base class shall only be used to reflect real is-a relations when specializing a derived class. For instance: A mammal is an animal, a primate is a mammal, homo sapiens is a primate, etc. Here the inheritance model is appropriate, but it would be wrong to derive from homo sapiens to reflect a human which is able to hunt using bows and arrows.

Therefore, a sortable model is not an unsortable model. Making a Django Model sortable enriches its functionality. In OOP design this does not qualify for an is-a relationship.

Fortunately, Python makes it very easy to distinguish between real is-a relationships and interfaces enriching their functionality. The latter are handled by mixin classes. They offer additional methods for classes without inheriting from the given base class.

Also consider the case when we want to augment some other functionality of a model class. If we also inherit from models.Model, we would create another abstract intermediate class. If we want to use both functional augmentations, we now are in trouble. We have to choose between one of the two, as we cannot inherit from both of them, because then our Django model would inherit from the base class models.Model twice. This kind of diamond-shaped inheritance shall be avoided.

By using a mixin to enrich an existing class with sorting functionality rather than inheriting from a special abstract base class, we can avoid these problems.


Copyright Jacob Rief and contributors.

Licensed under the terms of the MIT license.