Touch parent updated_at easily in Laravel

Touch parent updated_at easily in Laravel

When a model belongsTo or belongsToMany another model, such as a Comment which belongs to a Post, it is sometimes helpful to update the parent's timestamp when the child model is updated. For example, when a Comment model is updated, you may want to automatically "touch" the updated_at timestamp of the owning Post. Eloquent makes it easy. Just add a touches property containing the names of the relationships to the child model:

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Comment extends Model
{
    /**
     * All of the relationships to be touched.
     *
     * @var array
     */
    protected $touches = ['post'];

    /**
     * Get the post that the comment belongs to.
     */
    public function post()
    {
        return $this->belongsTo('App\Models\Post');
    }
}

Now, when you update a Comment, the owning Post will have its updated_at column updated as well, making it more convenient to know when to invalidate a cache of the Post model:

$comment = App\Models\Comment::find(1);

$comment->text = 'Edit to this comment!';

$comment->save();