public function _loadValidation($reload= false) {
        if (!$this->_validationLoaded || $reload == true) {
            $validation= $this->xpdo->getValidationRules($this->_class);
            $this->_validationLoaded= true;
            foreach ($validation as $column => $rules) {
                foreach ($rules as $name => $rule) {
                    $parameters = array_diff($rule, array($rule['type'], $rule['rule']));
                    $this->addValidationRule($column, $name, $rule['type'], $rule['rule'], $parameters);
                }
            }
        }
    }