How do I use django models.py classes in my own python programs?

Question

So, I want to make some changes in the database using python outsite Django, but I am unable to.

I'm trying to import the model from models.py but i'm unable to.

from models import NumberInfo

There is this error: 
Traceback (most recent call last):
  File "/home/sagan/p/matematika/matematika/mnumbers/prime_insert.py", line 1, in <module>
    from models import NumberInfo
  File "/home/sagan/p/matematika/matematika/mnumbers/models.py", line 5, in <module>
    class NumberInfo(models.Model):
  File "/home/sagan/.local/lib/python3.9/site-packages/django/db/models/base.py", line 108, in __new__
    app_config = apps.get_containing_app_config(module)
  File "/home/sagan/.local/lib/python3.9/site-packages/django/apps/registry.py", line 253, in get_containing_app_config
    self.check_apps_ready()
  File "/home/sagan/.local/lib/python3.9/site-packages/django/apps/registry.py", line 135, in check_apps_ready
    settings.INSTALLED_APPS
  File "/home/sagan/.local/lib/python3.9/site-packages/django/conf/__init__.py", line 82, in __getattr__
    self._setup(name)
  File "/home/sagan/.local/lib/python3.9/site-packages/django/conf/__init__.py", line 69, in _setup
    self._wrapped = Settings(settings_module)
  File "/home/sagan/.local/lib/python3.9/site-packages/django/conf/__init__.py", line 170, in __init__
    mod = importlib.import_module(self.SETTINGS_MODULE)
  File "/usr/lib/python3.9/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
ModuleNotFoundError: No module named 'matematika'```

Answer 1

If you want to edit database structure, just edit your models in models.py file and after that run

# creating new migrations based on the changes you have made to your models
$ python manage.py makemigrations

# applying and unapplying migrations
$ python manage.py migrate

Visit Django Documentation on Migrations to find out more!

Answer 2

Make sure you import the django python module and load the settings from the model's project before you try to import the model:

# add the django project to python's path so python can find it
# the variable path_of_python_project is the full path of the django project folder
sys.path.append(path_of_django_project)

# load django and the settings from your project
# I'm pretending your project is called django_projectname, you'll want to update that
import django
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'django_projectname.settings')

# setup django
django.setup()

# import your model and use it, just like you would in django
from django_projectname.models import NumberInfo
...