Can I avoid circular imports in Flask and SQLAlchemy

Take a look at this project: https://github.com/sloria/cookiecutter-flask
It’s a great example for doing things the right way. Many of great Flask features are used: blueprints, application factories and more.

Here is how they register extensions, such as SQLAlchemy Database:

# app/extensions.py
from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()
...


# app/app.py
from app.extensions import db

def create_app(config_object=ProdConfig):
    app = Flask(__name__.split('.')[0])
    app.config.from_object(config_object)
    register_extensions(app)
    ...

def register_extensions(app):
    db.init_app(app)
    ...