I can’t remember why I was installing Oracle Enterprise Linux 7 on Oracle VirtualBox a while back, but I did notice something interesting. It ships, just like CentOS 7, MariaDB Server 5.5. Presumably, this means that MariaDB is now supported by Oracle, too ;-) [jokes aside, It’s likely because OEL7 is meant to be 100% compatible to RHEL7]
The only reason I mention this now is Vadim Tkachenko, probably got his most retweeted tweet recently, stating just that. If you want to upgrade to MariaDB 10, don’t forget that the repository download tool provides CentOS 7 binaries, which should “just work”.
If you want to switch to MySQL, there is a Public Yum repository that MySQL provides (and also don’t forget to check the Extras directory of the full installation – from OEL7 docs sub-titled: MySQL Community and MariaDB Packages). Be sure to read the MySQL docs about using the Yum repository. I also just noticed that the docs now have information on replacing a third-party distribution of MySQL using the MySQL yum repository.