many to many attach laravel code example

Example 1: laravel has one through

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Mechanic extends Model
{
    /**
     * Get the car's owner.
     */
    public function carOwner()
    {
        return $this->hasOneThrough('App\Owner', 'App\Car');
    }
}

Example 2: one to many laravel

For example, a blog post may have an infinite number of comments. And a single
comment belongs to only a single post  

class Post extends Model
{
    public function comments()
    {
        return $this->hasMany('App\Models\Comment');
    }
}

class Comment extends Model
{
    public function post()
    {
        return $this->belongsTo('App\Models\Post');
    }
}

Example 3: laravel detach

// Detach a single role from the user...
$user->roles()->detach($roleId);

// Detach all roles from the user...
$user->roles()->detach();

Example 4: laravel attach

//id for single
$user->reasons->attach($reasonId);

//array for multiple
$user->reasons->attach($reasonIds);

$user->save();