Links to other modules

Modules in Mercur never reference each other directly. They’re connected through module links. The Product Attribute module links into Medusa’s product module in several ways: to products, to categories, and, for variant axes, to product options through mirror links. Once a link is defined, you retrieve related records with query.graph using the link alias.

const { data: products } = await query.graph({
  entity: "product",
  fields: ["id", "title", "scoped_attributes.*"],
})

Products

Link	Table	Relationship
Product → attribute (`scoped_attributes`)	None	Read-only; a product’s inline (product-scoped) attributes, resolved from `ProductAttribute.product_id`
Product ↔ attribute value	`product_attribute_value_link`	Many-to-many pivot; the values selected on a product

Link	Table	Relationship
Attribute ↔ category (`categories`)	`product_category_attribute`	Many-to-many; the product categories an attribute is associated with

Product options (mirror links)

Link	FK	Relationship
Attribute → option	`ProductAttribute.product_option_id`	Read-only 1:1; the mirror `ProductOption` for a variant-axis attribute
Value → option value	`ProductAttributeValue.product_option_value_id`	Read-only 1:1; the mirror `ProductOptionValue` for an axis value

The mirror links (Attribute → option, Value → option value) and the product scope link (scoped_attributes) are read-only. They’re resolved from the FK on the owning record and can’t be written through the link itself. The workflows keep the mirror in sync when axis attributes and values change.

Store

Catalog

Offer

Attribute

Product Edit

Order Group

Commission

Payout

Review

Products

Categories

Product options (mirror links)

​Products

​Categories

​Product options (mirror links)

Products

Categories

Product options (mirror links)