Django Extensible Models is a robust framework for dynamically extending Django models at runtime. It uses JSONFields for flexible data storage, with JSONSchema validation ensuring data integrity. It seamlessly integrates with Django's ORM while enabling multi-tenant schema variations.
** Why is it?
Django offers a really robust model system that functions as a great interface to store and retrieve data related to your app. Models in Django are backed by tables in a relational database. While this is really good for correctness, it is quite rigid in terms of the shape of data that is stored. Sometimes, you run into use-cases that demand a bit more dynamism during the running of your Django app.
Let's take a concrete example. You have an existing Django SaaS app that's launched to many happy customers. They are happy, but each customer feels that if they could store /just a little bit more custom data/ as part of their usage of your app, their workflows would be much smoother. So they ask you to add what they want. The trouble is, each customer is interested in augmenting their data in different ways. You diligently add the first customer's fields. And then another's. And then even more. And before you know it, things get really messy.
Solving this problem is the point of this project. Instead of individually catering to each of their requests, /Django Extensible Models/ offers you a general extension mechanism that allows your models to grow with your customers' needs.
With a relatively small change to your existing model code (see [[#installation][Installation]] and [[#usage][Usage]]), you now have a Django model that retains all its Django goodness, and can be extended on the fly with additional fields at runtime.
** DONE Formal schema for extended fields
We don't just stuff the extra data for these additional fields into a ~JSONField~ and call it a day,[fn::What sort of operation do you think this is?] we allow you to define a proper schema for this data (using [[https://jsonschema.net][JSON Schema]]).
** DONE Different extended schema for different groups of objects
It wouldn't make much sense to apply the same extension schema to all objects of your model,[fn::You could just update the Python model code of your app instead!] so Django Extensible Models allows you to define different extended fields for different sets of objects.
We also allow you to extended individual objects in unique ways if that is what you need.
** DONE Strong validation of data for these extended fields
With a good schema defined, it is easy to validate that incoming data for your extended fields match your expectations before storing it in the database.
** TODO Ability to query these fields using an ORM-friendly syntax
The data for your extended fields is not simply stored in a messy, impenetrable blob. It is stored in a structured [[https://docs.djangoproject.com/en/dev/ref/models/fields/#jsonfield][JSONField]] that can be queried in a systematic way using standard Django syntax.
TODO Dynamically generated forms for these extended fields in the Django Admin interface TODO Dynamic extensions for these fields in Django Model Forms (and Crispy Forms) TODO Dynamic extensions for these fields in for Django Rest Framework TODO Dynamic extensions for these fields in Django (Rest Framework) Filters ** TODO Migrations between versions of your extended schema!
Taken together, you should be able to use your extended fields much like how you use your native Django model fields. And this is just cool.
pip install django-extensible-models
INSTALLED_APPS = [
"extensible_models",
# ...]
EXTENSIBLE_MODELS_TENANT_MODEL = "your_app.YourTenantModel" EXTENSIBLE_MODELS_TENANT_FIELD = "your_tenant_field_name"
from django.db import models from extensible_models.models import ExtensibleModelMixin
class ExampleModel(ExtensibleModelMixin, models.Model):
...from django.contrib import admin
from extensible_models.admin import ExtensibleModelAdminMixin
class ExampleModelAdmin(ExtensibleModelAdminMixin, admin.ModelAdmin):
# Leave all your existing configuration as is!Copyright (c) 2022-2024 [[https://harishnarayanan.org][Harish Narayanan]]
This code is licenced under the MIT Licence. See [[https://github.com/hnarayanan/django-extensible-models-experiment/blob/main/LICENSE][LICENSE]] for the full text of this licence.