Models & Relationships

Eloquent Models

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\BelongsTo;
use Illuminate\Database\Eloquent\Relations\HasMany;

class Post extends Model
{
    protected $fillable = ["title", "body", "user_id"];

    protected function casts(): array
    {
        return [
            "published_at" => "datetime",
            "is_published" => "boolean",
            "metadata" => "array",
        ];
    }

    public function user(): BelongsTo
    {
        return $this->belongsTo(User::class);
    }

    public function comments(): HasMany
    {
        return $this->hasMany(Comment::class);
    }
}

Relationship Types

// One to One
public function profile(): HasOne {
    return $this->hasOne(Profile::class);
}

// One to Many
public function posts(): HasMany {
    return $this->hasMany(Post::class);
}

// Many to Many
public function roles(): BelongsToMany {
    return $this->belongsToMany(Role::class)
        ->withPivot("assigned_at")
        ->withTimestamps();
}

// Has Many Through
public function comments(): HasManyThrough {
    return $this->hasManyThrough(Comment::class, Post::class);
}

// Polymorphic
public function images(): MorphMany {
    return $this->morphMany(Image::class, "imageable");
}

Eager Loading

// Prevent N+1
$posts = Post::with("user", "comments")->get();

// Nested eager loading
$posts = Post::with("comments.user")->get();

// Lazy eager loading
$posts = Post::get();
$posts->load("user");

// Default eager loading on model
protected $with = ["user"];

Laravel 13: Model Improvements

Laravel 13 introduces #[Fillable] and #[Appends] attributes replacing $fillable and $appends properties for declarative configuration directly on the model class.