Cannot select MySQL/MariaDB in configure owncloud 7. It fixed at Mysql, no other selection http://www.howtoforge.com/how-to-install-owncloud-7-on-ubuntu-14.04
Did you upgraded from any older ubuntu distribution to Ubuntu 14.04? If it is a fresh Ubuntu14.04 machine then it should be working with the Mariadb server installation, beacasue fresh Ubuntu 14.04 is loaded with the Mariadb 5.5 version. Please paste output of
