Use on-device SQL database instead of discovering files

I'm using Pocketbook Era with ebook subscription service. Majority of my ebooks are DRMd (non-standard) which means that majority of the files discovered by Calibre do not have any readable metadata.

Would it be possible for Calibre to use on-device SQL database for device sync instead of discovering files? Database file is easily accessible and contains all necessary metadata, both for the DRMd ebooks as well as those without it.