There are, but they’re pretty niche because their performance is really bad. Niche enough I can’t recall a single name today. But really, my advice for early p

There are, but they’re pretty niche because their performance is really bad. Niche enough I can’t recall a single name today. But really, my advice for early prototyping is split in two: either keep it in memory and serialize to disk, or use SQLite. Note that even using serialized memory constructs will require data migrations, aka schema updates.