How to Create Migrations

In this document, you’ll learn how to create a Migration using Typeorm on your Medusa server.

Step 1: Create Migration File

To create a migration that makes changes to your Medusa schema, run the following command:

npx typeorm migration:create -n UserChanged --dir src/migrations

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This will create the migration file in the path you specify. You can use this without the need to install Typeorm's CLI tool. You can then go ahead and make changes to it as necessary.

The migration file must be inside the src/migrationsCopy to Clipboard directory. When you run the build command, it will be transpiled into the directory dist/migrationsCopy to Clipboard. The migrations runCopy to Clipboard command can only pick up migrations under the dist/migrationsCopy to Clipboard directory on a Medusa server. This applies to migrations created in a Medusa server, and not in a Medusa plugin. For plugins, check out the Plugin's Structure section.

Generating Migrations for Entities

You can alternatively use Typeorm's generateCopy to Clipboard command to generate a Migration file from existing entity classes. As Medusa uses v0.2.45 of Typeorm, you have to create a ormconfig.jsonCopy to Clipboard first before using the generateCopy to Clipboard command.

Typeorm will be updated to the latest version in v1.8.0 of Medusa.

For example, create the file ormconfig.jsonCopy to Clipboard in the root of your Medusa server with the following content:

{
  "type": "postgres",
  "host": "localhost",
  "port": 5432,
  "username": "<YOUR_DB_USERNAME>",
  "password": "<YOUR_DB_PASSWORD>",
  "database": "<YOUR_DB_NAME>",
  "synchronize": true,
  "logging": false,
  "entities": [
    "dist/models/**/*.js"
  ],
  "migrations": [
    "dist/migrations/**/*.js"
  ],
  "cli": {
      "entitiesDir": "src/models",
      "migrationsDir": "src/migrations"
  }
}

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Make sure to replace <YOUR_DB_USERNAME>Copy to Clipboard, <YOUR_DB_PASSWORD>Copy to Clipboard, and <YOUR_DB_NAME>Copy to Clipboard with the necessary values for your database connection.

Then, after creating your entity, run the buildCopy to Clipboard command:

npm

npm run build

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Yarn

yarn run build

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Finally, run the following command to generate a Migration for your new entity:

npx typeorm@0.2.45 migration:generate -n PostCreate

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Where PostCreateCopy to Clipboard is just an example of the name of the migration to generate. The migration will then be generated in src/migrations/<TIMESTAMP>-PostCreate.tsCopy to Clipboard. You can then skip to step 3 of this guide.

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Step 2: Write Migration File

The migration file contains the necessary commands to create the database columns, foreign keys, and more.

You can learn more about writing the migration file in You can learn more about writing migrations in Typeorm’s Documentation.

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Step 3: Build Files

Before you can run the migrations you need to run the build command to transpile the TypeScript files to JavaScript files:

npm

npm run build

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Yarn

yarn run build

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Step 4: Run Migration

The last step is to run the migration with the command detailed earlier

medusa migrations run

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If you check your database now you should see that the change defined by the migration has been applied successfully.

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What’s Next

• Set up your development server.