import { CodeTabs, CodeTab, Table } from "docs-ui"

export const metadata = { title: Links between Promotion Module and Other Modules, }

{metadata.title}

This document showcases the module links defined between the Promotion Module and other Commerce Modules.

Summary

The Promotion Module has the following links to other modules:

Read-only links are used to query data across modules, but the relations aren't stored in a pivot table in the database.

</Note> <Table> <Table.Header> <Table.Row> <Table.HeaderCell> First Data Model </Table.HeaderCell> <Table.HeaderCell> Second Data Model </Table.HeaderCell> <Table.HeaderCell> Type </Table.HeaderCell> <Table.HeaderCell> Description </Table.HeaderCell> </Table.Row> </Table.Header> <Table.Body> <Table.Row> <Table.Cell> [Cart](/references/cart/models/Cart) in [Cart Module](../../cart/page.mdx) </Table.Cell> <Table.Cell> [Promotion](/references/promotion/models/Promotion) </Table.Cell> <Table.Cell> Stored - many-to-many </Table.Cell> <Table.Cell> [Learn more](#cart-module) </Table.Cell> </Table.Row> <Table.Row> <Table.Cell> [LineItemAdjustment](/references/cart/models/LineItemAdjustment) in [Cart Module](../../cart/page.mdx) </Table.Cell> <Table.Cell> [Promotion](/references/promotion/models/Promotion) </Table.Cell> <Table.Cell> Read-only - has one </Table.Cell> <Table.Cell> [Learn more](#cart-module) </Table.Cell> </Table.Row> <Table.Row> <Table.Cell> [Order](/references/order/models/Order) in [Order Module](../../order/page.mdx) </Table.Cell> <Table.Cell> [Promotion](/references/promotion/models/Promotion) </Table.Cell> <Table.Cell> Stored - many-to-many </Table.Cell> <Table.Cell> [Learn more](#order-module) </Table.Cell> </Table.Row> </Table.Body> </Table>

Cart Module

A promotion can be applied on line items and shipping methods of a cart. Medusa defines a link between the Cart and Promotion data models.

Medusa also defines a read-only link between the Cart Module's LineItemAdjustment data model and the Promotion data model. Because the link is read-only from the LineItemAdjustment's side, you can only retrieve the promotion applied on a line item, and not the other way around.

Retrieve with Query

To retrieve the carts that a promotion is applied on with Query, pass carts.* in fields:

<Note>

To retrieve the promotion of a line item adjustment, pass promotion.* in fields.

</Note> <CodeTabs group="relation-query"> <CodeTab label="query.graph" value="method">

const { data: promotions } = await query.graph({
  entity: "promotion",
  fields: [
    "carts.*",
  ],
})

// promotions[0].carts

</CodeTab> <CodeTab label="useQueryGraphStep" value="step">

import { useQueryGraphStep } from "@medusajs/medusa/core-flows"

// ...

const { data: promotions } = useQueryGraphStep({
  entity: "promotion",
  fields: [
    "carts.*",
  ],
})

// promotions[0].carts

</CodeTab> </CodeTabs>

Manage with Link

To manage the promotions of a cart, use Link:

import { Modules } from "@medusajs/framework/utils"

// ...

await link.create({
  [Modules.CART]: {
    cart_id: "cart_123",
  },
  [Modules.PROMOTION]: {
    promotion_id: "promo_123",
  },
})

</CodeTab> <CodeTab label="createRemoteLinkStep" value="step">

import { Modules } from "@medusajs/framework/utils"
import { createRemoteLinkStep } from "@medusajs/medusa/core-flows"

// ...

createRemoteLinkStep({
  [Modules.CART]: {
    cart_id: "cart_123",
  },
  [Modules.PROMOTION]: {
    promotion_id: "promo_123",
  },
})

</CodeTab> </CodeTabs>

Order Module

An order is associated with the promotion applied on it. Medusa defines a link between the Order and Promotion data models.

Retrieve with Query

To retrieve the orders a promotion is applied on with Query, pass orders.* in fields:

const { data: promotions } = await query.graph({
  entity: "promotion",
  fields: [
    "orders.*",
  ],
})

// promotions[0].orders

</CodeTab> <CodeTab label="useQueryGraphStep" value="step">

import { useQueryGraphStep } from "@medusajs/medusa/core-flows"

// ...

const { data: promotions } = useQueryGraphStep({
  entity: "promotion",
  fields: [
    "orders.*",
  ],
})

// promotions[0].orders

</CodeTab> </CodeTabs>

Manage with Link

To manage the promotion of an order, use Link:

import { Modules } from "@medusajs/framework/utils"

// ...

await link.create({
  [Modules.ORDER]: {
    order_id: "order_123",
  },
  [Modules.PROMOTION]: {
    promotion_id: "promo_123",
  },
})

</CodeTab> <CodeTab label="createRemoteLinkStep" value="step">

import { Modules } from "@medusajs/framework/utils"
import { createRemoteLinkStep } from "@medusajs/medusa/core-flows"

// ...

createRemoteLinkStep({
  [Modules.ORDER]: {
    order_id: "order_123",
  },
  [Modules.PROMOTION]: {
    promotion_id: "promo_123",
  },
})

</CodeTab> </CodeTabs>