Sequelize

Promise-based Node.js ORM for Postgres, MySQL, MariaDB, SQL Server, and SQLite.

Migrations

• Seed and migration files are named with a YYYYMMDDHHmmss timestamp prefix (14 digits) so they apply in order.

# Generate the timestamp prefix for a file name
echo "$(date +'%Y%m%d%H%M%S')-test.js"

npx sequelize-cli migration:generate --name add-orders-table
npx sequelize-cli db:migrate
npx sequelize-cli db:migrate:undo          # roll back the last
npx sequelize-cli db:seed:all

Notes

• A migration must define both up (apply) and down (revert) — an irreversible down is a deploy hazard.
• Migrations run in filename (timestamp) order; never edit a migration that’s already run in shared environments — add a new one.
• Watch the N+1 problem: use include (eager loading) deliberately; log generated SQL in dev (logging: console.log).