protected function setFieldKey()
    {
        if (! $this->fieldValue || ! $this->rootValue) {
            return;
        }

        $cacheFieldKey = $this->fieldValue
            ->getParent()
            ->getCacheKey();

        if ($cacheFieldKey) {
            $this->fieldKey = data_get($this->rootValue, $cacheFieldKey);
        }
    }