4.2.1. Define Link Between a Brand and a Product

1. Define the Link Between Product and Brand#

Links are defined in a TypeScript or JavaScript file under the src/links directory. The file defines and exports the link using the defineLink function imported from @medusajs/utils.

So, create the file src/links/product-brand.ts with the following content:

src/links/product-brand.ts
1import BrandModule from "../modules/brand"2import ProductModule from "@medusajs/product"3import { defineLink } from "@medusajs/utils"4
5export default defineLink(6  {7    linkable: ProductModule.linkable.product,8    isList: true,9  },10  BrandModule.linkable.brand11)

The defineLink function accepts two parameters, each specifying the link configurations of each data model.

Modules have a special linkable property that holds the data models' link configurations.

defineLink accepts for each parameter either:

• The data model's link configuration;
• Or an object that has two properties:
  • linkable: the link configuration of the data model.
  • isList: Whether many records of the data model can be linked to the other model.

So, in the above code snippet, you define a link between the Product and Brand data models. Since isList is enabled on the product's side, a brand can be associated with multiple products.

2. Sync the Link to the Database#

To reflect your link in the database, run the db:sync-links command:

Terminal
❯npx medusa db:sync-links

This creates a table for the link in the database. The table stores the IDs of linked brand and product records.

Next: Link Brand and Product Records#

In the next chapter, you'll learn how to associate brand and product records by creating a link between them.