How to use models between multiple apps? - django

Question

I'm building a Django app and I was asked split apart models.py and put the resulting models in a 'models' folder. I did that and it works fine.
I was then asked to move the models folder to the Project level so that the models can be used by other apps.
The file structure would look like this (taken from the Django tutorial):
mysite
mysite
polls
db.sqlite3
manage.py
models <- Have the poll app's models in there?
However, everything I have read suggests this is heavily frowned upon and that models should live at the app level, not the project level.
So, what is the best way to handle this is Django -- to let models be used by multiple applications? Some of the things I have read suggest importing models between apps or changing the models Meta class db_table option.
A majority of the posts I have found are from 5+ years ago though, so I'm not sure what the best current approach is.
If I import models to a new app, and then /do something with them, do they point to the same database as the app they were imported from or is a new database created for the new app?
Thanks for the help. Very appreciated.

Answer 1

I was wondering the same thing and saw you got a decent answer from reddit, but thought I'd throw my 2 cents in.
You could refactor the models into individual apps.
tl;dr
Some assumptions about your situation
At first, the models were split out from models.py into individual python files to improve maintainability
The models were moved up to the project level to minimize impact to the models by changes in the applications (or vice versa)
So for an example:
mysite
├── polls
│ ├── __init__.py
│ ├── admin.py
│ ├── apps.py
│ ├── migrations
│ │ └── __init__.py
│ ├── models
│ │ └── __init__.py
│ │ └── foo.py
│ │ └── bar.py
│ ├── tests.py
│ └── views.py
├── db.sqlite3
├── manage.py
└── mysite
├── __init__.py
├── settings.py
├── urls.py
└── wsgi.py
We have 2 models (foo and bar) that we separated for some logical reason.
IMHO, I think that overall maintainability could benefit by putting the foo and bar models in their own apps IF they satisfy 2 criteria
They are categorically different
They are used by multiple applications
At this point, the models can be imported by other apps in your site just as before, but the layout looks more like the Django best practices
New Layout:
mysite
├── polls
├── foo
│ └── models.py
│ └── etc...
├── bar
│ └── models.py
│ └── etc...
├── etc...

Answer 2

It's a good question, when you start programming in Django they tell you (Django project team) that an application is like a module, but they do not tell you how to do it.
You can do it as Rohan says in the comment to your question: "You can refer models from one app into another using 'appname.model_name' in the relationship fields.", but you must keep in mind that the concept of application in Django is thought to make these modules reusable, according to that the best option would be to orient your applications to services or another architecture that allows you to uncouple The applications of your project, look rest framework as an option