This is a tiny script I used to pack a bunch of libretro rdb files into a single sqlite database.
From within this folder:
git clone https://github.com/libretro/libretro-database git clone https://github.com/libretro/RetroArch cd RetroArch/libretro-db make cp ./libretrodb_tool ../.. # If needed, customize the list of entries in libretro-sqlite-db.py cd ../.. python3 libretro-sqlite-db.py