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

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

# {metadata.title}

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

## Summary

The Currency Module has the following links to other modules:

<Note title="Tip">

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>
        [StoreCurrency](/references/store/models/StoreCurrency) in [Store Module](../../store/page.mdx)
      </Table.Cell>
      <Table.Cell>
        [Currency](/references/currency/models/Currency)
      </Table.Cell>
      <Table.Cell>
        Read-only - has one
      </Table.Cell>
      <Table.Cell>
        [Learn more](#store-module)
      </Table.Cell>
    </Table.Row>
  </Table.Body>
</Table>
---

## Store Module

The Store Module has a `Currency` data model that stores the supported currencies of a store. However, these currencies don't hold all the details of a currency, such as its name or symbol.

Instead, Medusa defines a read-only link between the [Store Module](../../store/page.mdx)'s `StoreCurrency` data model and the Currency Module's `Currency` data model. Because the link is read-only from the `Store`'s side, you can only retrieve the details of a store's supported currencies, and not the other way around.

### Retrieve with Query

To retrieve the details of a store's currencies with [Query](!docs!/learn/fundamentals/module-links/query), pass `supported_currencies.currency.*` in `fields`:

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

```ts
const { data: stores } = await query.graph({
  entity: "store",
  fields: [
    "supported_currencies.currency.*",
  ],
})

// stores[0].supported_currencies[0].currency
```

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

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

// ...

const { data: stores } = useQueryGraphStep({
  entity: "store",
  fields: [
    "supported_currencies.currency.*",
  ],
})

// stores[0].supported_currencies[0].currency
```

  </CodeTab>
</CodeTabs>