Laravel Eloquent: Return Array key as the fields ID
Stefan Izdrail
Founder & Senior Architect · 2026-06-29
Title: Efficiently Retrieving Array Keys as IDs using Laravel Eloquent
Introduction
Laravel provides an incredible framework for building web applications. One of the key features is its powerful Object Relational Mapper (ORM) called Eloquent. It simplifies database interactions and ensures efficient management of data. However, at times, we may need to return array keys as their corresponding IDs. In this blog post, we will provide a comprehensive explanation on how to achieve this using Laravel's Eloquent ORM.
The Concept of Array Keys as IDs
When working with large datasets or performing specific operations that involve looking up entries based on the ID, it becomes impractical to refer to an index value instead of an understandable ID. In such cases, we can instruct Laravel Eloquent to return array keys as their associated IDs. This eliminates confusion and reduces the likelihood of errors during lookup or validation processes.
Approach 1: Using Collection's 'keyBy()' Method
The Laravel's Collection class offers a convenient method called 'keyBy()'. It enables us to convert an array into another one in which the original keys are replaced with new ones based on a specified criteria. In this case, we can use it to create new arrays where each item has its key as the respective ID.
Here's how you would implement this method:
1. Retrieve the result from Eloquent using either 'first()', 'get()', or 'getModel()'.
In your controller, write:
```php
$users = User::all();
// or
$user = User::find(1);
```
2. Pass the result to Collection's 'keyBy()' method with a custom closure that assigns the ID as the key.
```php
$collectionWithIdAsKey = \Collect::make($users)->keyBy(function ($user) {
return (int) $user->id;
});
```
Approach 2: Customizing Eloquent Model's 'toArray()' Method
Alternatively, you can customize your Eloquent model's 'toArray()' method to return the array keys as IDs. This approach is useful if you want all your models within a specific application to follow this convention.
1. Create a Trait called 'CustomArrayKeyModelAttribute':
```php
namespace App\Traits;
trait CustomArrayKeyModelAttribute
{
/**
* Return the model as an array, with keys set as their respective IDs.
* @return array
*/
public function toArrayCustomIdKeys()
{
return $this->toArray();
}
}
1. Add this trait to your Eloquent Model:
```php
use App\Traits\CustomArrayKeyModelAttribute;
class User extends Model
{
use CustomArrayKeyModelAttribute;
// Other model code...
}
```
2. In your controller, get the data as usual:
```php
$users = User::all();
```
3. Use 'toArrayCustomIdKeys()' method to return an array with IDs as keys:
```php
$collectionWithIdAsKey = $users->toArrayCustomIdKeys();
```
Conclusion
By following the approaches provided, you can efficiently achieve your goal of retrieving arrays where their keys are set as their respective IDs. This makes it easier to perform operations based on the ID or use array_key_exists methods for effective data management. For more information and tutorials on Laravel Eloquent, feel free to visit our website: https://laravelcompany.com.