My website used to work from my local server (Ubuntu 16.04 Apache 2 Server). Then I planned to migrate it to another real server. So I wanted to link OJS database to real server. Long story short, someone suggested me to purge remove the mysql/mariadb on my local server and reinstall. When I removed and reinstalled mariadb-server-10.0, now my website shows this: 
Can someone help me what exactly I should do here?
Also I found an old backup of mysql folder on my portable hard drive. Should I just replace the whole folder and will it solve the problem?