Sequelize is a great ORM for NodeJS applications that are built on relational backends. Inevitably, you'll need to update your models as the database requirements change.. or if you did something silly. Here's a real life approach to using Sequelize to doing database migrations.

Khalil Stemmler

A real-world walkthrough of fixing a production data integrity issue caused by a missing unique constraint in a Sequelize model. The author discovered 639 duplicate 'area of study' entries in a MySQL database because the unique constraint was defined in the Sequelize model but never applied in the original migration script. The fix involves writing a Sequelize migration that: fetches all duplicate records, reassigns foreign key relationships to the canonical IDs, deletes the excess rows, and finally adds the missing unique constraint to the database table via queryInterface.addConstraint.

Fixing Sequelize Models with Migrations