Southern writes:  

One of the most important tasks any developer needs to do often is back up their MySQL database. In many cases, the database is what drives most of the site. While most web hosts do a daily backup of a customer's database, relying on them to make backups and provide them at no cost is risky to say the least. That's why I've created a database backup function that I can call whenever I want -- including nightly CRONs.

The PHP & MySQL Code
more: david walsh