在根目录中设置默认数据库

This may be an insanely easy thing to do, but I'm completely lost. I'm working off of a server which is currently hosting two websites: the older site, and the newer wordpress site. The default database on the server is currently for the older site and I'm trying to figure out how to switch it so that the wordpress database is the default, and that site displays instead of the old one. I have access to the server and can login through mysql, but am not sure where to go from there. Any help?This may be an insanely easy thing to do, but I