public function getValidationRules()
    {
        $rules = parent::getValidationRules();

        foreach ($rules as &$rule) {
            if ($rule !== '_unique') {
                continue;
            }

            $model = $this->resolvePath();
            $table = $model->getTable();

            $rule = 'unique:'.$table.','.$this->getModelAttributeKey();
            if ($model->exists) {
                $rule .= ','.$model->getKey();
            }
        }
        unset($rule);

        return [$this->getPath() => $rules];
    }