We can not fix corrupted databases for customers. The only thing I can suggest to try is the basic maintenance feature in the Database Manager but that is unlikely to fix any sort of significant corruption. There are possible ways to fix corrupt databases if you google search things like 'fix corrupt postgresql database' but they are complicated and hard to understand or do if you don't have a background in development or coding.
This is why regular backups are a good idea. If your database becomes corrupt, or you have hardware problems, you can restore a backup and only have to import the most recent hands (that were played after the backup was created) and edit any tournament results if necessary. I recommend keeping at least the most recent 2 or 3 backups in case the most recent one does not restore properly you can try the previous backup.
Here is a FAQ explaining how to backup your database and all settings in one easy step.