Inserting and Updating Related Models with Laravel Eloquent

Insert & Update Related Models

Eloquent provides convenient methods for adding related models. For example, to add a new Comment to a Post you can create the comment instance and call the save method on the comments relationship, which automatically fills the post_id foreign key.

$comment = new App\Comment(['message' => 'A new comment.']);
$post = App\Post::find(1);
$post->comments()->save($comment);

To save multiple related models you can use saveMany :

$post = App\Post::find(1);
$post->comments()->saveMany([
    new App\Comment(['message' => 'A new comment.']),
    new App\Comment(['message' => 'Another comment.'])
]);

Creating Related Models

Besides save and saveMany , you can use create which accepts an attribute array and persists the model in one step. create works with plain arrays, while save expects a full model instance.

$post = App\Post::find(1);
$comment = $post->comments()->create(['message' => 'A new comment.']);

You can also use createMany to create several related models at once:

$post = App\Post::find(1);
$post->comments()->createMany([
    ['message' => 'A new comment.'],
    ['message' => 'Another new comment.']
]);

Updating a belongsTo Relationship

When updating a belongsTo relation, use associate to set the foreign key on the child model, and dissociate to null it.

$account = App\Account::find(10);
$user->account()->associate($account);
$user->save();

$user->account()->dissociate();
$user->save();

Many‑to‑Many Relationships

Attach / Detach

Use attach to insert a record into the pivot table and detach to remove it. Both methods accept an ID or an array of IDs, and you can pass additional pivot data.

$user = App\User::find(1);
$user->roles()->attach($roleId);
$user->roles()->attach($roleId, ['expires' => $expires]);
$user->roles()->detach($roleId);
$user->roles()->detach(); // remove all

Sync

sync replaces the pivot table records with the given ID array, removing any IDs not present. syncWithoutDetaching adds new IDs without removing existing ones.

$user->roles()->sync([1, 2, 3]);
$user->roles()->syncWithoutDetaching([1, 2, 3]);

Toggle

toggle will attach IDs that are not currently attached and detach those that are.

$user->roles()->toggle([1, 2, 3]);

Saving Pivot Data

You can pass extra data when saving a related model with save on a many‑to‑many relation.

App\User::find(1)->roles()->save($role, ['expires' => $expires]);

Updating Existing Pivot Records

Use updateExistingPivot to modify a pivot row.

$user->roles()->updateExistingPivot($roleId, $attributes);

Updating Parent Timestamps

When a child model belonging to a parent (e.g., Comment belongs to Post ) is updated, you can automatically touch the parent’s updated_at timestamp by defining a $touches property on the child model.

<?php
namespace App;
use Illuminate\Database\Eloquent\Model;

class Comment extends Model
{
    protected $touches = ['post'];

    public function post()
    {
        return $this->belongsTo('App\Post');
    }
}

Now updating a comment will also update the related post’s updated_at field, helping with cache invalidation.

$comment = App\Comment::find(1);
$comment->text = 'Edit to this comment!';
$comment->save();