Instale y configure la extensión

Writing raw SQL by hand gets messy fast. An ORM lets you work with Python objects and rows feel like normal classes. 🗃️

Flask-SQLAlchemy is the official extension that wires SQLAlchemy into Flask, so your app gets a clean, ready-to-use database layer.

You add it like any dependency. pip pulls in Flask-SQLAlchemy and the SQLAlchemy core it builds on automatically.

You make one SQLAlchemy instance, usually named db. Every model and query you write later will hang off this single object.

Flask needs to know where your data lives. The SQLALCHEMY_DATABASE_URI setting is a connection string pointing at your database.

For learning, SQLite is perfect: it lives in one file, needs no server, and the URI is just a path on disk.

After config, you connect the extension to your app with init_app. This hands Flask-SQLAlchemy everything it needs to run.

You can pass the app straight to SQLAlchemy(app) for tiny apps, or use init_app later to keep db reusable across setups.

Only the URI changes between SQLite, PostgreSQL, or MySQL. Your models and queries stay identical, which makes switching painless.

Set SQLALCHEMY_TRACK_MODIFICATIONS to False. It silences a warning and avoids extra overhead you almost never need.

Once configured, db gives you Model for tables, Column for fields, and session for saving. You will meet each of these soon.

Which config key tells Flask-SQLAlchemy where your database lives?

You installed the extension, created a db object, set the URI, and bound it with init_app. Your app is ready for models. 🎉