From personal experience with the rtcom-eventlogger database, I would say that if it's really just corruption, and not you had the file get deleted or something, then it should be fixable.

(I figured out how to consistently fix it manually when I got those well-known issues where your messages get stuck looking like they're sending, or stop saving, because it eventually really pissed me off having no good options for fixing it that f'ing corruption of the conversations, call logs and the like are stored in the same database, so I suspect it would be doable to fix).

I don't have an 'easy' tutorial or anything for you. What I was going to do was eventually post the massive thing of notes I wrote up when I was figuring this out, then maybe post a tutorial for how to fix the database when it did the kind of corruptions that I'm used to dealing with (note, in all of my cases, the entire history doesn't just disappear). Then some day I wanted to try to write a program that would automate the fix that I nowadays to manually... But yeah, that's off in the distance by several months at least.

Anyway, the other issue is that I don't think the ring tone is stored in that database (though maybe it is, idk), so it's quite possible you have some other issue going on than just having database corruption.

What you can do for now is run
Then see if you can figure out by looking at it in a text editor what went wrong. If you're not familiar with SQL, that probably would take some time at best, or be too daunting to know where to begin at worse. If you're okay with the possibility of people reading your messages/chats/contacts information, you can give that file to someone else who may be able to fix it. I'm okay with volunteering to try, but I won't be able to get to it for a few days, plus you have no reason to trust me with whatever might be in your call/message/chat history.

That's all I got for now.