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Flask · Module 5 of 10

Databases with SQLAlchemy

Store data using Flask-SQLAlchemy models.

📖 Key ideas

  1. pip install flask-sqlalchemy.
  2. Define models: class User(db.Model): id = db.Column(db.Integer, primary_key=True).
  3. Add and commit: db.session.add(u); db.session.commit().
  4. Query: db.session.execute(db.select(User).filter_by(email=e)).scalar_one_or_none().
  5. Flask-Migrate (Alembic) manages schema changes.
💡 Real-life example: The session is a shopping cart: add items, then pay (commit) once.
SQLAlchemyPython SQL toolkit and ORM
db.ModelBase class for models
db.sessionUnit of work for DB changes
Flask-MigrateAlembic migrations for Flask