Flask-SQLAlchemy

Adds SQLAlchemy support to Flask. Under development.

Install the package:

pip install Flask-SQLAlchemy

In your Flask app, import the extension and initialize the DB:

from flaskext.sqlalchemy import SQLAlchemy
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:////code/apicurious/db.sqlite'
app.config['SQLALCHEMY_ECHO'] = True
db = SQLAlchemy(app)

Instead of declaring your models via declarative_base() as you usually would with SQLAlchemy, subclass from db.Model:

class Note(db.Model):
    __tablename__ = "notes"

    id   = db.Column(db.Integer, primary_key=true)
    text = db.Column(db.String(length=255))

    def __init__(self, text):
        self.text = text

To create the database tables, run:

db.create_all()

If you've set app.config['SQLALCHEMY_ECHO'] = True, you will see the SQL statments that the database will execute:

2012-03-12 12:15:07,793 INFO sqlalchemy.engine.base.Engine PRAGMA table_info("notes")
2012-03-12 12:15:07,793 INFO sqlalchemy.engine.base.Engine ()
2012-03-12 12:15:07,794 INFO sqlalchemy.engine.base.Engine
CREATE TABLE notes (
        id INTEGER NOT NULL,
        text VARCHAR(255),
        PRIMARY KEY (id)
)


2012-03-12 12:15:07,794 INFO sqlalchemy.engine.base.Engine ()
2012-03-12 12:15:07,794 INFO sqlalchemy.engine.base.Engine COMMIT

To create a record, use db.session.add. For more information on sessions, refer to the SQLAchemy documention on sessions:

note = Note('Hello World')
db.session.add(note)
db.session.commit()

To query, use <Model>.query:

>>> print Note.query.get(1).text
'Hello World'