django models = business logic + data access? Or data access layer should be separated out from django model?

Question

In Django, the suggested software architecture is to put all business logic and data access in models.

But, some colleagues have suggested that the data access layer sho

Answer 1

After three years of Django development, I've learned the following.

The ORM is the access layer. Nothing more is needed.

50% of the business logic goes in the model. Some of this is repeated or amplified in the Forms.

20% of the business logic goes in Forms. All data validation, for example, is in the forms. In some cases, the forms will narrow a general domain (allowed in the model) to some subset that's specific to the problem, the business or the industry.

20% of the business logic winds up in other modules in the application. These modules are above the models and forms, but below the view functions, RESTful web services and command-line apps.

10% of the business logic winds up in command-line apps using the management command interface. This is file loads, extracts, and random bulk changes.

It's very important that view functions and RESTful web services do approximately nothing. They use models, forms, and other modules as much as possible. The view functions and RESTful web services are limited to dealing with the vagaries of HTTP and the various data formats (JSON, HTML, XML, YAML, whatever.)

Trying to invent Yet Another Access Layer is a zero-value exercise.