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.
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 and 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.
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
JSON Schema).
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.
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.
The data for your extended fields is not simply stored in a messy, impenetrable blob. It is stored in a structured JSONField that can be queried in a systematic way using standard Django syntax.
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# settings.py
INSTALLED_APPS = [
# ...
"extensible_models",
# ...
]
EXTENSIBLE_MODELS_TENANT_MODEL = "your_app.YourTenantModel"
EXTENSIBLE_MODELS_TENANT_FIELD = "your_tenant_field_name"# models.py
from django.db import models
from extensible_models.models import ExtensibleModelMixin
class ExampleModel(ExtensibleModelMixin, models.Model):
...# admin.py
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 Harish Narayanan
This code is licenced under the MIT Licence. See LICENSE for the full text of this licence.