VersionPress\Storages\MetaEntityStorage::transformToParentEntityField PHP Method

    private function transformToParentEntityField($values)
    {
        $joinedKey = $this->createJoinedKey($this->maybeReplacePrefixWithPlaceholder($values[$this->keyName]), $values['vp_id']);
        $data = ['vp_id' => $values[$this->parentReferenceName], $joinedKey => $values[$this->valueName]];
        return $data;
    }