One-to-One: hasOne&belongsTo

Contoh kasus: User memiliki satu Profile.

users
  id, name, email

profiles
  id, user_id, bio, avatar, website

Model User:

class User extends Model
{
    // User punya satu profile
    public function profile(): \Illuminate\Database\Eloquent\Relations\HasOne
    {
        return $this->hasOne(Profile::class);
    }
}

Model Profile:

class Profile extends Model
{
    // Profile milik satu user
    public function user(): \Illuminate\Database\Eloquent\Relations\BelongsTo
    {
        return $this->belongsTo(User::class);
    }
}

Cara penggunaan:

$user = User::find(1);

// Akses profile dari user
$bio = $user->profile->bio;

// Buat profile untuk user
$user->profile()->create([
    'bio'    => 'Laravel enthusiast',
    'avatar' => 'avatar.jpg',
]);

// Akses user dari profile
$profile = Profile::find(1);
$name    = $profile->user->name;

One-to-Many: hasMany& belongsTo

Contoh kasus: User memiliki banyak Post.

users
  id, name

posts
  id, user_id, title, body

Model User:

class User extends Model
{
    // User punya banyak post
    public function posts(): \Illuminate\Database\Eloquent\Relations\HasMany
    {
        return $this->hasMany(Post::class);
    }
}

Model Post:

class Post extends Model
{
    // Post milik satu user
    public function user(): \Illuminate\Database\Eloquent\Relations\BelongsTo
    {
        return $this->belongsTo(User::class);
    }
}

Cara penggunaan:

$user = User::find(1);

// Ambil semua post user
$posts = $user->posts;

// Ambil post yang dipublish saja
$published = $user->posts()->where('published_at', '!=', null)->get();

// Tambah post baru
$user->posts()->create([
    'title' => 'Post Baru',
    'body'  => 'Konten post...',
]);

// Hitung jumlah post
$count = $user->posts()->count();

Kunci Foreign Key

Laravel otomatis menebak foreign key dengan konvensi {nama_model}_id. Kamu bisa override jika berbeda:

// Jika foreign key bukan 'user_id' tapi 'author_id'
public function posts(): HasMany
{
    return $this->hasMany(Post::class, 'author_id');
}

Ringkasan Episode 2