multiple subdomain and one copy of site

In many website there are multiple sub domain for different category. for example suppose a site address is www.test.com. now we can create sub domain http://ift.tt/20w7j1E. Is it possible to i had one copy of site template but two database for these domains? it means i have two database one for test.com and another for category.test.com but both of them use same file to show site front end and there is just one copy of site files in server. is it possible?