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Migrations

In this document, you'll learn what Migrations are in Medusa.

Medusa’s Migrations do not work with SQLite databases. They are intended to be used with PostgreSQL databases, which is the recommended database for using Medusa in production.

What are Migrations​

Migrations are scripts that are used to make additions or changes to your database schema. In Medusa, they are essential for both when you first install your backend and for subsequent backend upgrades later on.

When you first create your Medusa backend, the database schema used must have all the tables necessary for the backend to run.

When a new Medusa version introduces changes to the database schema, you'll have to run migrations to apply them to your own database.

Migrations are used to apply changes to the database schema. However, there are some version updates of Medusa that require updating the data in your database to fit the new schema. Those are specific to each version and you should check out the version under Upgrade Guides for details on the steps.

How to Run Migrations​

Migrations in Medusa can be done in one of two ways:

Migrate Command​

Using the Medusa CLI tool, you can run migrations with the following command:

medusa migrations run

This will check for any migrations that contain changes to your database schema that aren't applied yet and run them on your backend.

Seed Command​

Seeding is the process of filling your database with data that is either essential or for testing and demo purposes. In Medusa, the seed command will run the migrations to your database if necessary before it seeds your database with dummy data.

You can use the following command to seed your database:

npm run seed

This will use the underlying seed command provided by Medusa's CLI to seed your database with data from the file data/seed.json on your Medusa backend.

Custom Development​

Developers can create custom entities in the Medusa backend, a plugin, or in a Commerce Module, then ensure it reflects in the database using a migration.