Create file in home directory called .mylogin.cnf
add the following

[client]
user = username
password = password

set permissions to
chmod 600 /home/alienfactory/.mylogin.cnf

Cron all DB

0 1 * * * /usr/bin/mysqldump --defaults-extra-file=/home/alienfactory/.mylogin.cnf -u username --single-transaction --quick --lock-tables=false --all-databases > full-backup-$(date +\%F).sql

Cron Specific DB

0 1 * * * /usr/bin/mysqldump --defaults-extra-file=/home/alienfactory/.mylogin.cnf -u app_user --single-transaction --quick --lock-tables=false --databases wordpress > wordpress-backup-$(date +\%F).sql