Laravel:Relations OneToMany,ManyToMany,OneToOne....

1. Relation "Un à Un" (One to One) - User et Profile

php artisan make:migration create_Utilisateurs_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('Utilisateurs', function (Blueprint $table) {
            $table->id();//id int primary key
            $table->string('name');
            $table->string('email')->unique();
            $table->string('password');
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('Utilisateurs');
    }
};

php artisan make:model Models\Utilisateur

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Utilisateur extends Model
{
    protected $table = 'Utilisateurs';
    protected $primaryKey = 'id';
    public $timestamps = true;

    protected $fillable = [
        'name', 'email', 'password'
    ];

    // Relation Un à Un : Un utilisateur a un seul profil
    public function profile()
    {
        return $this->hasOne('App\Models\Profile'); 
		//lorsque le model profile a primaryKey=id ,on n'as pas besoin de spécifier idProfile dans la relation has.. ,belongsTo...
    }
}

php artisan make:migration create_profiles_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('profiles', function (Blueprint $table) {
            $table->id();
            $table->foreignId('Utilisateur_id')->constrained();//permet de créer la foreign key Utilisateur_id qui references Utlisateur(id)
			//constraint foreign key('Utilisateur_id') references Utilisateur(id)
			//lorsque Utilisateur a primarykey=id  ,pour déclarer une foreign key  on appell Model_id dans ce cas Utilisateur_id
            $table->text('bio')->nullable();
            $table->string('avatar')->nullable();
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('profiles');
    }
};

php artisan make:model Models\Profile

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Profile extends Model
{
    protected $table = 'profiles';
    protected $primaryKey = 'id';
    public $timestamps = true;

    protected $fillable = [
        'Utilisateur_id', 'bio', 'avatar'
    ];

    // Relation Un à Un inverse : Un profil appartient à un utilisateur
    public function Utilisateur()
    {
        return $this->belongsTo('App\Models\Utilisateur');
    }
}

2. Relation "Un à Plusieurs" (One to Many) - Author et Book

php artisan make:migration create_authors_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('authors', function (Blueprint $table) {
            $table->id();
            $table->string('name');
            $table->string('email')->unique();
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('authors');
    }
};

php artisan make:model Models\Author

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Author extends Model
{
    protected $table = 'authors';
    protected $primaryKey = 'id';
    public $timestamps = true;

    protected $fillable = [
        'name', 'email'
    ];

    // Relation Un à Plusieurs : Un auteur peut avoir plusieurs livres
    public function books()
    {
        return $this->hasMany('App\Models\Book');
    }
}

php artisan make:migration create_books_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('books', function (Blueprint $table) {
            $table->id();
            $table->foreignId('author_id')->constrained();
            $table->string('title');
            $table->text('description');
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('books');
    }
};

php artisan make:model Models\Book

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Book extends Model
{
    protected $table = 'books';
    protected $primaryKey = 'id';
    public $timestamps = true;

    protected $fillable = [
        'author_id', 'title', 'description'
    ];

    // Relation Un à Plusieurs inverse : Un livre appartient à un auteur
    public function author()
    {
        return $this->belongsTo('App\Models\Author');
    }
}

3. Relation "Plusieurs à Plusieurs" (Many to Many) - Student et Course

php artisan make:migration create_students_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('students', function (Blueprint $table) {
            $table->id();
            $table->string('name');
            $table->string('email')->unique();
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('students');
    }
};

php artisan make:model Models\Student

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Student extends Model
{
    protected $table = 'students';
    protected $primaryKey = 'id';
    public $timestamps = true;

    protected $fillable = [
        'name', 'email'
    ];

    // Relation Plusieurs à Plusieurs : Un étudiant peut être inscrit à plusieurs cours
    public function courses()
    {
        return $this->belongsToMany('App\Models\Course');
    }
}

php artisan make:migration create_courses_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('courses', function (Blueprint $table) {
            $table->id();
            $table->string('title');
            $table->text('description');
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('courses');
    }
};

php artisan make:model Models\Course

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Course extends Model
{
    protected $table = 'courses';
    protected $primaryKey = 'id';
    public $timestamps = true;

    protected $fillable = [
        'title', 'description'
    ];

    // Relation Plusieurs à Plusieurs inverse : Un cours peut avoir plusieurs étudiants
    public function students()
    {
        return $this->belongsToMany('App\Models\Student');
    }
}

4. Relation Polymorphe - Comment et Post

php artisan make:migration create_comments_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('comments', function (Blueprint $table) {
            $table->id();//id int primary key
            $table->text('content');
            $table->unsignedBigInteger('commentable_id');
            $table->string('commentable_type');
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('comments');
    }
}

php artisan make:model Models\Comment

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Comment extends Model
{
    protected $table = 'comments';
    protected $primaryKey = 'id';
    public $timestamps = true;

    protected $fillable = [
        'content', 'commentable_id', 'commentable_type'
    ];

    // Relation Polymorphe : Un commentaire peut appartenir à un post ou à une vidéo
    public function commentable()
    {
        return $this->morphTo();
    }
};

php artisan make:migration create_posts_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('posts', function (Blueprint $table) {
            $table->id();
            $table->string('title');
            $table->text('content');
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('posts');
    }
};

php artisan make:model Models\Post

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Post extends Model
{
    protected $table = 'posts';
    protected $primaryKey = 'id';
    public $timestamps = true;

    protected $fillable = [
        'title', 'content'
    ];

    // Relation Polymorphe inverse : Un post peut avoir plusieurs commentaires
    public function comments()
    {
        return $this->morphMany('App\Models\Comment', 'commentable');
    }
}

la Relation Polymorphe - Video

php artisan make:migration create_videos_table

<?php

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

return new class extends Migration
{
    public function up()
    {
        Schema::create('videos', function (Blueprint $table) {
            $table->id();
            $table->string('title');
            $table->text('description');
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('videos');
    }
};

php artisan make:model Models\Video

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class Video extends Model
{
    protected $table = 'videos';
    protected $primaryKey = 'id';
    public $timestamps = true;

    protected $fillable = [
        'title', 'description'
    ];

    // Relation Polymorphe inverse : Une vidéo peut avoir plusieurs commentaires
    public function comments()
    {
        return $this->morphMany('App\Models\Comment', 'commentable');
    }
}

Utilisation des Relations

<?
// Création d'un utilisateur
$Utilisateur = Utilisateur::create([
    'name' => 'John Doe',
    'email' => 'john@example.com',
    'password' => bcrypt('secret'),
]);

// Création d'un profil pour l'utilisateur
$profile = $Utilisateur->profile()->create([
    'bio' => 'A passionate Laravel developer.',
    'avatar' => 'avatar.jpg',
]);
Exemple d'Utilisation de la Relation Un à Plusieurs
php
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// Création d'un auteur
$author = Author::create([
    'name' => 'Jane Author',
    'email' => 'jane@example.com',
]);

// Ajout de plusieurs livres pour l'auteur
$book1 = $author->books()->create([
    'title' => 'Book 1',
    'description' => 'Description for Book 1',
]);

$book2 = $author->books()->create([
    'title' => 'Book 2',
    'description' => 'Description for Book 2',
]);
Exemple d'Utilisation de la Relation Plusieurs à Plusieurs
php
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// Création d'un étudiant
$student = Student::create([
    'name' => 'Alice Student',
    'email' => 'alice@example.com',
]);

// Inscrit l'étudiant à plusieurs cours
$course1 = Course::create([
    'title' => 'Course 1',
    'description' => 'Description for Course 1',
]);

$course2 = Course::create([
    'title' => 'Course 2',
    'description' => 'Description for Course 2',
]);

$student->courses()->attach([$course1->id, $course2->id]);
Exemple d'Utilisation de la Relation Polymorphe
php
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// Création d'un post
$post = Post::create([
    'title' => 'My First Post',
    'content' => 'This is the content of my first post.',
]);

// Ajout de commentaires au post
$comment1 = $post->comments()->create([
    'content' => 'Great post!',
]);

$comment2 = $post->comments()->create([
    'content' => 'I enjoyed reading this.',
]);

// Création d'une vidéo
$video = Video::create([
    'title' => 'Laravel Tutorial',
    'description' => 'A tutorial on Laravel basics.',
]);

// Ajout de commentaires à la vidéo
$comment3 = $video->comments()->create([
    'content' => 'Very helpful tutorial.',
]);

$comment4 = $video->comments()->create([
    'content' => 'Thanks for sharing!',
]);