Has this ever happened to you? It has for a forum and wordpress blog of mine. I never touched it. The sites were setup with minimal content but the mysql db and db username just got deleted. Is it most likely that the web host is responsible?
Somebody with access to a MySQL DB user. To find out how it happened, are you able to review logs? Also, is your host ignoring the question? It must be a free host, right?
dedicated server, I doubt its hacked because I have other sites on it and no problem there. And the site affected is not really active. Could it be a server config problem. My host is looking into it but it's taking them time to figure it out.