public function existingOnly()
    {
        $value = [
            'Filename' => $this->getFilename(),
            'Variant' => $this->getVariant(),
            'Hash' => $this->getHash()
        ];
        /** @var DBFile $file */
        $file = DBField::create_field('DBFile', $value);
        $file->setAllowGeneration(false);
        return $file;
    }