Что означает вот эта конструкция?

["product_id":protected]=> int(973)

abstract class BaseSProducts extends ShopBaseObject  implements Persistent
{
 
    /**
     * Peer class name
     */
    const PEER = 'SProductsPeer';
 
    /**
     * The Peer class.
     * Instance provides a convenient way of calling static methods on a class
     * that calling code may not be able to identify.
     * @var        SProductsPeer
     */
    protected static $peer;
 
    /**
     * The value for the id field.
     * @var        int
     */
    protected $id;
 
    /**
     * The value for the name field.
     * @var        string
     */
    protected $name;
 
    /**
     * The value for the url field.
     * @var        string
     */
    protected $url;
    
    
    //////////////////
    protected $name_color;
    protected $color;
    protected $color_image;
    /////////////////
    
    
    /**
     * The value for the active field.
     * @var        boolean
     */
    protected $active;
 
    /**
     * The value for the hit field.
     * @var        boolean
     */
    protected $hit;
 
    /**
     * The value for the hot field.
     * @var        boolean
     */
    protected $hot;
 
    /**
     * The value for the action field.
     * @var        boolean
     */
    protected $action;
 
    /**
     * The value for the brand_id field.
     * @var        int
     */
    protected $brand_id;
 
    /**
     * The value for the category_id field.
     * @var        int
     */
    protected $category_id;
 
    /**
     * The value for the related_products field.
     * @var        string
     */
    protected $related_products;

echo "Its name is " , get_class($model) , "\n";

echo "\$model->getParentId() = ". $model->getParentId()

print $model->getParentId()

 public function getParentId() {
               return $this->parent_id;
             }

$models = SProductsQuery::create()
                    ->orderByCreated(Criteria::DESC)
                    ->where('SProducts.Id NOT IN ?', $this->getId())
                    ->filterByCategoryId($this->getCategoryId())
                    ->filterByHot(1)
                    ->limit($limit)
                    ->find();

 public function getParentId() {
               return $this->aMainCategory->parent_id;
             }