Yes, I don't understand "declarative" approach at all, it seems too wasteful and roundabout to me. You want to change something? You go and change it. That simple. I hate it when callbacks are abstracted away from me. Abstractions over callbacks always feel like they're getting in the way, not helping me.

> Also, why do you use SQL and databases? Couldn’t you just modify files on the filesystem?

Anyone can read a MySQL data file. IIRC the format is pretty straightforward. The whole point of doing it through the real MySQL server is to make use of indexes, the query optimizer, and proper handling of concurrency, at least. Sure you can reimplement those things, but at this point congrats, you've just reimplemented the very database system you were trying to avoid, just worse.