MySQL database

sudo apt-get install mysql-common mysql-server mysql-client libmysqlclient10 libmysqlclient10-dev mysql-doc

Accept configuration defaults, except say Yes to starting MySQL when the system boots up.

Move databases into /var/db:

sudo /etc/init.d/mysql stop
sudo mkdir -p /var/db
sudo mv /var/lib/mysql /var/db/mysql
sudo ln -s /var/db/mysql /var/lib/mysql

In /etc/mysql/my.cnf, comment out skip-networking. Restart mysql:

sudo /etc/init.d/mysql start

Set the root password:

mysqladmin -u root password 'pick_a_good_password'
sudo /etc/init.d/mysql restart