database-migration

Create database migrations by running `uv run alembic revision --autogenerate -m "descriptive message"` after modifying your SQLAlchemy models. Alembic auto-generates migration files that define schema changes, which you can review before applying them to your database.

Yes. Review the generated migration files to verify upgrade and downgrade paths before application. This lets you catch issues, add data transformations, or create indexes and constraints manually before running `uv run alembic upgrade head` to apply migrations to your target database.

Alembic migrations are reversible by design. Each migration includes both upgrade and downgrade functions, allowing you to roll back schema changes safely. Test downgrade paths to ensure you can revert changes if needed across your QA and production environments.

Alembic can auto-generate migrations from SQLAlchemy model changes, but you can also create empty migrations for custom logic like data transformations, index creation, or constraint additions that auto-generation doesn't capture.

Create migrations that include custom Python code in the upgrade and downgrade functions to transform, migrate, or validate data alongside schema changes. This lets you handle complex operations like renaming columns, recalculating values, or populating new fields safely.

Write descriptive migration messages that clearly explain what schema or data changes occur. Keep migrations small, focused, and reversible. Version control migration files to track all schema evolution, enabling safe collaboration and deployment across QA and production backends.