Unable to Start MySQL on Fedora System Boot

This evening, I was updating a set of web development tools on my Fedora 20 machine, including Apache 2.4.9, PHP 5.5.12 and MySQL 5.5.37. After that, I started all the services and enabled them to run on startup. But I cannot enable MySQL service with the following command (as usual):

# systemctl enable mysqld.service
Failed to issue method call: No such file or directory

After did some research on this issue, I found that MariaDB is a binary drop in replacement of the same MySQL version (on Fedora 20). So that MySQL 5.5 will be compatible with MariaDB 5.5.

# mysql --version
mysql  Ver 15.1 Distrib 5.5.37-MariaDB, for Linux (x86_64) using readline 5.1

To be able to start MySQL server when system boot, you must enable mariadb.service.

# systemctl enable mariadb.service
ln -s '/usr/lib/systemd/system/mariadb.service' '/etc/systemd/system/multi-user.target.wants/mariadb.service'

# systemctl start mariadb.service