Laravel: N to N (mysql) relation using Eloquent ORM - php

Question

I got 4 tables:
// Table countries
+----+------+
| Id | Name |
+----+------+
| 1 | USA |
| 2 | GB |
+----+------+
// Table platforms
+----+---------+
| Id | Name |
+----+---------+
| 1 | Windows |
| 2 | Linux |
+----+---------+
// Table users
+----+-------+------------+-------------+
| Id | Name | country_id | platform_id |
+----+-------+------------+-------------+
| 1 | Admin | 1 | 1 |
| 2 | Test | 2 | 1 |
+----+-------+------------+-------------+
// Table posts
+----+-----------+------------+-------------+---------+
| Id | Title | country_id | platform_id | user_id |
+----+-----------+------------+-------------+---------+
| 1 | TestPost1 | 2 | 1 | 1 |
| 2 | TestPost2 | 2 | 2 | null |
+----+-----------+------------+-------------+---------+
The database should be able to implement the following relations:
User (N) <-> (N) Platform
User (N) <-> (N) Country
User (0..1) <-> (N) Post
Post (N) <-> (N) Country
Post (N) <-> (1) Platform
So now I tried to implement these relations following Laravel Eloquent ORM documentation:
// Country.php
public function posts()
{
return $this->belongsToMany('App\Post');
}
public function users()
{
return $this->belongsToMany('App\User');
}
// Platform.php
public function users()
{
return $this->belongsToMany('App\User');
}
public function posts()
{
return $this->belongsToMany('App\Post');
}
// User.php
public function posts()
{
return $this->hasMany('App\Post');
}
public function countries()
{
return $this->hasMany('App\Country');
}
public function platforms()
{
return $this->hasMany('App\Platform');
}
// Post.php
public function countries()
{
return $this->hasMany('App\Country');
}
public function platforms()
{
return $this->hasMany('App\Comment');
}
public function user()
{
return $this->belongsTo('App\User', 'user_id');
}
But now I am confused, as I thought the way to implement N to N relations in mysql is to add a third table to db, for example like that:
// Table CountryUserRelations to implement User (N) <-> (N) Country
+----+------------+---------+
| Id | country_id | user_id |
+----+------------+---------+
| 1 | 1 | 1 |
| 2 | 2 | 1 |
| 3 | 1 | 2 |
| 4 | 2 | 2 |
+----+------------+---------+
But how does Eloquent ORM handle the rules inside my model? Will it keep the N to N relations without having to add a relations table? Or am I missing something or misunderstanding the Eloquent ORM Relations concept?

Answer 1

I just joined stackoverflow so I do not have enough credit to comment so I will leave an asnwer here.
First of all please correct your relationship definition.
in User Model:( you have mistake here)
public function countries(){
return $this->belongsToMany(Country::class);
}
and in your Country Model:
public function users(){
return $this->belongsToMany(User::class);
}
second you need to create country_user table using:
php artisan make:migration create_country_user_table
after it you need to complete your table:
Schema::create('country_user', function (Blueprint $table){
$table->increments('id');
$table->unsignedInteger('country_id');
$table->unsignedInteger('user_id');
$table->foreign('country_id')->references('id')->on('countries');
$table->foreign('user_id')->references('id')->on('users');
}