FlaskMigrate

Flask-Migrate is an extension for the Flask web framework that handles database migrations for SQLAlchemy-backed applications. It integrates the Alembic migration tool with Flask, providing a simple, consistent interface to evolve database schemas as models change over time.

Designed to work with SQLAlchemy and the Flask application structure, Flask-Migrate stores migration scripts in a migrations directory and uses the database metadata defined by your models to generate changes. It exposes a set of CLI commands under the flask db namespace, including init to create the migration repository, migrate to autogenerate a new migration based on model changes, and upgrade or downgrade to apply or revert migrations. Additional commands allow viewing history, stamping a database with a specific revision, and inspecting current status.

Typical workflow: define or modify SQLAlchemy models, run flask db migrate -m "message" to generate a migration, review the generated script, and run flask db upgrade to apply it to the database. The app can be created using an application factory, with Migrate(app, db) or migrate = Migrate() and later migrate.init_app(app, db).

Flask-Migrate is maintained as a Flask extension and depends on Flask, SQLAlchemy, and Alembic. It is widely used to coordinate database evolution in development, testing, and production environments and supports multiple database backends supported by SQLAlchemy.