---
url: "https://vueda.dev/v3/reference/api/js/utils/reverseForeignKey/functions/isReverseForeignKey.md"
title: "isReverseForeignKey"
---

# isReverseForeignKey

## Overview

Report whether a field is a reverse foreign key, such as an order's `items` when each item has a foreign key to its order.

A form sends an unexpanded reverse foreign key as a list of primary keys. The server applies that list with the related manager's `set()`. When the foreign key is not nullable, `set()` only adds rows, so selecting another parent's row moves it to this parent and removing a row from the list removes nothing. Forms therefore show the field read-only, and create and update views leave it out of the default `submitFields`. A view that names the field in `expand` edits its rows as an inline instead.

## Signature

`isReverseForeignKey(field)`

### Parameters

| Name | Type | Required | Description |
| --- | --- | --- | --- |
| <span id="param-field">field</span> | [FieldInfo](/v3/reference/api/js/stores/storeModelInfo/types/FieldInfo.md) | yes | The field's model info. |

### Returns

`boolean`

Whether model info describes the field as a reverse foreign key.

## Source

`client/lib/utils/reverseForeignKey.js:14`