I've been using SQLAlchemy with Flask via the Flask extension Flask-SQLAlchemy. Everything works great so far, but I foresee a potential problem once I start to use my database model outside of Flask. In the future I'd like to be able to use my models with non-Flask SQLAlchemy (a worker daemon process or with a PySide interface). "Well just use standard SQLAlchemy," you may say, " and fore-go the use of the extension". That was my first thought, but sadly some useful extensions (notably Flask-DebugToolbar) seem to like using the extension version and it is nice to be able to have Flask manage the database sessions in the way that it does. I'd like to not throw the baby out with the bath water.
I realize that this is somewhat specific to Flask, but is there a way that I could do both? Can I create models with standard SQLAlchemy declarative and then somehow inject them into Flask-SQLAlchemy's way of doing things? If it helps with the solution, I don't need to use any of the Model specific methods that Flask-SQLAlchemy provides (get_or_404, paginate, etc..) and I also specify a __tablename__ for all of my models, so I don't rely on Flask-SQLAlchemy generating that for me. I took a look at the source of Flask-SQLAlchemy (https://github.com/mitsuhiko/flask-sqlalchemy/blob/master/flask_sqlalchemy.py) and from what I can tell it seems that it's using Flask's signalling capabilities by customizing SQLAlchemy's session and mapper, but that is where my understanding ends (I'm still new to this whole stack, Python, Flask, SQLAlchemy) and I could use some pointers for how to proceed. To visualize what I'm talking about, here are the two types of models. A basic Flask-SQLAlchemy model looks like (http://packages.python.org/Flask-SQLAlchemy/quickstart.html#a-minimal-application): from flask import Flask from flask.ext.sqlalchemy import SQLAlchemy app = Flask(__name__) app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////tmp/test.db' db = SQLAlchemy(app) class User(db.Model): id = db.Column(db.Integer, primary_key=True) username = db.Column(db.String(80), unique=True) email = db.Column(db.String(120), unique=True) def __init__(self, username, email): self.username = username self.email = email def __repr__(self): return '<User %r>' % self.username Note the db.Model, db.Integer and db <dot> everything. The plain declarative SQLAlchemy equivalent would be (http://flask.pocoo.org/docs/patterns/sqlalchemy/): from sqlalchemy import Column Integer, String, create_engine from sqlalchemy.orm import scoped_session, sessionmaker from sqlalchemy.ext.declarative import declarative_base engine = create_engine('sqlite:////tmp/test.db', convert_unicode=True) db_session = scoped_session(sessionmaker(autocommit=False, autoflush=False, bind=engine)) Base = declarative_base() Base.query = db_session.query_property() class User(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) name = Column(String(50), unique=True) email = Column(String(120), unique=True) def __init__(self, name=None, email=None): self.name = name self.email = email def __repr__(self): return '<User %r>' % (self.name) Thanks for your help! -- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To view this discussion on the web visit https://groups.google.com/d/msg/sqlalchemy/-/fyqvIAUBbcsJ. To post to this group, send email to sqlalchemy@googlegroups.com. To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en.
