CodeToLive

Flask Database Integration

Flask can work with various databases through extensions like Flask-SQLAlchemy, Flask-MongoEngine, and others.

Flask-SQLAlchemy


from flask_sqlalchemy import SQLAlchemy

app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///site.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(20), unique=True, nullable=False)
    email = db.Column(db.String(120), unique=True, nullable=False)
    password = db.Column(db.String(60), nullable=False)

    def __repr__(self):
        return f"User('{self.username}', '{self.email}')"

Database Initialization


# Create tables
with app.app_context():
    db.create_all()

CRUD Operations


# Create
user = User(username='john', email='john@example.com')
db.session.add(user)
db.session.commit()

# Read
users = User.query.all()
user = User.query.filter_by(username='john').first()

# Update
user.email = 'new@example.com'
db.session.commit()

# Delete
db.session.delete(user)
db.session.commit()

Database Migrations


pip install flask-migrate
            

from flask_migrate import Migrate

migrate = Migrate(app, db)
            

flask db init
flask db migrate -m "Initial migration"
flask db upgrade

Flask-MongoEngine


from flask_mongoengine import MongoEngine

app.config['MONGODB_SETTINGS'] = {
    'db': 'your_database',
    'host': 'mongodb://localhost/your_database'
}
db = MongoEngine(app)

class User(db.Document):
    username = db.StringField(required=True)
    email = db.StringField(required=True)

Database Best Practices

Next: User Authentication