Many to Many Eloquent Relationship Laravel Tutorial

Hi Guys,

In this tutorial, we will see how to use many to many relationship in Laravel 9 with an example. Many to many relationship is a little bit complicated than one to one and one to many relationships. Laravel many to many eloquent relationship; Through this tutorial, i am going to show you what is many to many relationship and how to use many to many relationship in laravel 9 application. An example of a many-to-many relationship is a user that has many roles and those roles are also shared by other users in the application.

So in this tutorial, you can understand how to create many-to-many relationships with migration with a foreign key schema for one to many relationships, use sync with a pivot table, create records, attach records, get all records, delete, update, where condition and everything related to many to many relationship.

In this example, i will create "users", "roles" and "role_user" tables. each table is connected with each other. now we will create many to many relationships with each other by using the laravel Eloquent Model. We will first create database migration, then model, retrieve records and then how to create records too. So you can also see database table structure on below screen.

Laravel 9 many to many relationship is slightly more complicated than hasOne and hasMany relationships.

So, let's start following example:

composer create-project laravel/laravel example-app

Now we have to create migration of "users", "roles" and "role_user" table. we will also add foreign key with users and roles table. so let's create like as below:

<?php
  
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
  
return new class extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->id();
            $table->string('name');
            $table->string('email')->unique();
            $table->timestamp('email_verified_at')->nullable();
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });
    }
    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('users');
    }
};

php artisan make:migration create_roles_table

<?php
  
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
  
return new class extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('roles', function (Blueprint $table) {
            $table->id();
            $table->string('name');
            $table->timestamps();
        });
    }
  
    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('roles');
    }
};

php artisan make:migration create_role_user_table

<?php
  
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
  
return new class extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('role_user', function (Blueprint $table) {
            $table->foreignId('user_id')->constrained('users');
            $table->foreignId('role_id')->constrained('roles');
        });
    }
    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {   
        Schema::dropIfExists('role_user');
    }
};

Here, we will create User, Role and UserRole table model. we will also use "belongsToMany()" for relationship of both model.

<?php
  
namespace App\Models;
  
use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;
use Laravel\Sanctum\HasApiTokens;
  
class User extends Authenticatable
{
    use HasApiTokens, HasFactory, Notifiable;
  
    /**
     * The attributes that are mass assignable.
     *
     * @var array

     */
    protected $fillable = [
        'name',
        'email',
        'password',
    ];
  
    /**
     * The attributes that should be hidden for serialization.
     *
     * @var array

     */
    protected $hidden = [
        'password',
        'remember_token',
    ];
  
    /**
     * The attributes that should be cast.
     *
     * @var array

     */
    protected $casts = [
        'email_verified_at' => 'datetime',
    ];
  
    /**
     * The roles that belong to the user.
     */
    public function roles()
    {
        return $this->belongsToMany(Role::class, 'role_user');
    }
}

php artisan make:model Role

<?php
  
namespace App\Models;
  
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
  
class Role extends Model
{
    use HasFactory;
  
    /**
     * The users that belong to the role.
     */
    public function users()
    {
        return $this->belongsToMany(User::class, 'role_user');
    }
}

php artisan make:model UserRole

<?php
  
namespace App\Models;
  
use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;
  
class UserRole extends Model
{
    use HasFactory;
      
}

$user = User::find(1);  
 
dd($user->roles);

$role = Role::find(1);  
 
dd($role->users);

$user = User::find(2);  
 
$roleIds = [1, 2];
$user->roles()->attach($roleIds);

$user = User::find(3);  
 
$roleIds = [1, 2];
$user->roles()->sync($roleIds);

$role = Role::find(1);  
 
$userIds = [10, 11];
$role->users()->attach($userIds);

$role = Role::find(2);  
 
$userIds = [10, 11];
$role->users()->sync($userIds);

I hope you understand of many to many relationship...