public function getParentId()
    {
        return (is_string($this->parentAttribute) && !empty($this->parentAttribute)) ?
        $this->{$this->parentAttribute} : null;
    }
public function getParentId()
    {
        return (is_string($this->parentAttribute) && !empty($this->parentAttribute)) ?
        $this->{$this->parentAttribute} : null;
    }
public function getParentId ( ) { return ( is_string ( $ this -> parentAttribute ) && ! empty ( $ this -> parentAttribute ) ) ? $ this -> { $ this -> parentAttribute } : null ; }
Get parent ID.
@return string|null null if parent attribute isn't enabled.
Get parent ID .