laravel how does fillable match with database table code example

Example 1: model observer laravel

namespace App;

use Illuminate\Database\Eloquent\Model;

class Post extends Model
{
    protected $table = 'posts';

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

    protected static function boot()
    {
        parent::boot();
        static::saving(function ($model) {
            $model->slug = str_slug($model->title);
        });
    }
}

Example 2: larave Soft Deletes

Schema::table('flights', function (Blueprint $table) {
    $table->softDeletes();
});