SQLite db and flask

Steps to create and use an SQLite db with a flask app. Assumes using flask factory project structure.

Requirements:

Flask-SQLAlchemy
Flask-Migrate

Create models in models.py, e.g

class Stock(db.Model):
    symbol = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(20), unique=False)
    created = db.Column(db.DateTime, index=True, default=datetime.utcnow)

def __init__(self, **kwargs):
    super(Stock, self).__init__(**kwargs)

def __repr__(self):
    return '<Stock {} {}>'.format(self.symbol, self.name)

Point to sqlite db in config.py

SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or \
    'sqlite:///' + os.path.join(PROJECT_ROOT, 'stocks.db')

In extensions.py add

from flask_sqlalchemy import SQLAlchemy
db = SQLAlchemy()
from flask_migrate import Migrate
migrate = Migrate(db=db)

In factory.py add

def register_extensions(app):
    from application.extensions import db, migrate
    db.init_app(app)
    migrate.init_app(app=app)

    # need this line for flask db migrate to find models
    from application import models

Create the migration repository (folder)

flask db init

Create migrations -> do this each time you make a change to a model

flask db migrate -m "change message"

Apply the changes with

flask db upgrade