mySQL backup script & cronjob
Hi!I've got no idea in the world about what I'm doing here, so seeking help from experts

Our school runs a forum and is now too large to backup fully via phpmyadmin and I've been advised I need to create a "cronjob" and a "shell script" to create a mySQL backup of a database running off Plesk 7
First time I had ever heard the word "cronjob"

So basically if anybody could help, what do I need to achieve a mysql database backup once a week on an early Sunday morning (in gzip format is preferred if possible) to output to a folder on our server called root/private
Our database details are
db - forum
u - forumuser
p - forumpass
and it is in the path of ourdomain.edu/forum/index.php
in our Plesk panel there is a crontab tab - so assuming I would want for 3am Sundays (if I worked this out right)
Minute 0
Hour 3
Day of the Month *
Month *
Day of the Week 0
Command (command for the script I need?)
So I think I have the "cronjob" part worked out (maybe?) - just need a "shell script" now to spit out the backup
Thanks
