django-eav

Introduction

django-eav provides an Entity-Attribute-Value storage model for django apps.

For a decent explanation of what an Entity-Attribute-Value storage model is, check Wikipedia.

Note

This software was inspired / derived from the excellent eav-django written by Andrey Mikhaylenko.

There are a few notable differences between this implementation and the eav-django implementation.

• This one is called django-eav, whereas the other is called eav-django.
• This app allows you to to 'attach' EAV attributes to any existing django model (even from third-party apps) without making any changes to the those models' code.
• This app has slightly more robust (but still not perfect) filtering.

Installation

From Github

You can install django-eav directly from guthub:

pip install -e git+git://github.com/mvpdev/django-eav.git#egg=django-eav

Prerequisites

Django Sites Framework

As of Django 1.7, the Sites framework is not enabled by default; Django-EAV requires this framework. To enable the sites framework, follow these steps:

Add django.contrib.sites to your INSTALLED_APPS setting. Be sure to add sites to the installed apps list BEFORE eav!

Define a SITE_ID setting:

SITE_ID = 1

Run migrate

Usage

Edit settings.py

Add eav to your INSTALLED_APPS in your project's settings.py file. Be sure to add eav to the installed apps list AFTER the sites framework!

Register your model(s)

Before you can attach eav attributes to your model, you must register your model with eav:

>>> import eav
>>> eav.register(MyModel)

Generally you would do this in your models.py immediate after your model declarations. Alternatively, you can use the registration decorator provided:

from eav.decorators import register_eav
@register_eav()
class MyModel(models.Model):
    ...

Create some attributes

>>> from eav.models import Attribute
>>> Attribute.objects.create(name='Weight', datatype=Attribute.TYPE_FLOAT)
>>> Attribute.objects.create(name='Color', datatype=Attribute.TYPE_TEXT)

Assign eav values

>>> m = MyModel()
>>> m.eav.weight = 15.4
>>> m.eav.color = 'blue'
>>> m.save()
>>> m = MyModel.objects.get(pk=m.pk)
>>> m.eav.weight
15.4
>>> m.eav.color
blue

>>> p = MyModel.objects.create(eav__weight = 12, eav__color='red')

Filter on eav values

>>> MyModel.objects.filter(eav__weight=15.4)

>>> MyModel.objects.exclude(name='bob', eav__weight=15.4, eav__color='red')

Documentation and Examples

http://mvpdev.github.com/django-eav