I'm sure it's theoretically possible to write a database that only allows reads/inserts and that runs off a CD-R burner, but it's weird that I haven't seen that in the wild. Seems like something that should be doable with SQLite's VFS support (and in fact I'm pretty sure the existing demo VFS for read-only support gets you most of the way there).
In any case, "write-once" media can still be rewritten; the same lasers that etch data into a CD-R can do so to destroy the same data. You're going to want redundancy/backups and you're going to want each new row in the table to cryptographically reference the previous (such that any data destruction invalidates all subsequent rows) - by which point you've reinvented most of what constitutes a blockchain anyway.
I guess I should have specified that I was being a bit tongue in cheek.
I do believe Write-Once was actually a thing with the banking mainframe I was acquainted with in my youth. It wasn't a CD-R thing, it was just an IBM thing which enforced write-only at the BIOS/Hardware level. Honestly, I'm not sure, I was young and impressionable :D. IOW, I might have been misled.
Anyway... All you need is logically write-once with proper signing, audits, etc. and you'll be just as close to unforgeable, etc. etc. as reality demands.
Heck, even journald on Linux provides unforgeable log entries. It is vulnerable to a destruction attack, so whatevs. Everything is. Even a blockchain -- witness the rugpulls.
> by which point you've reinvented most of what constitutes a blockchain anyway.
I love that.
Anyway, I'm here to dissuade you. Do whatever you want. Just be aware of the potential consequences.
In any case, "write-once" media can still be rewritten; the same lasers that etch data into a CD-R can do so to destroy the same data. You're going to want redundancy/backups and you're going to want each new row in the table to cryptographically reference the previous (such that any data destruction invalidates all subsequent rows) - by which point you've reinvented most of what constitutes a blockchain anyway.