This app can generate a DBML output for all installed models.
pip install django-dbml
'...',
'django_dbml',
'...',
$ python manage.py dbml
To generate DBML for a subset of your models, specify one or more Django app names or models by app_label or app_label.ModelName. Related tables will still be included in the DBML.
The initial code was based on https://github.com/hamedsj/DbmlForDjango project