maybe you could use the issue template which i’m getting presented when creating a new thread in this “Server” category and also explain what this means (maybe with some screenshots?):
I think others are only able to help you if you provide more information about your environment (e.g. operating system, database, database version, specific database configuration). Those are all questions asked in that template which i think are asked for a good reason.
At the moment nearly everything is missing (e.g. possible entries from log files which could be really useful and could show you some hints on the issue), even the ownCloud version you are using (e.g. an outdated ownCloud version could cause this problem).