A tiny .htaccess .htaccess / General Guides
This is mostly a "stick this in your application" tutorial. The file only does two things, and only on Apache servers, and we explained them as simply as we could. But they offer HUGE functionality for web developers, so take the time to read about it.
MySQL - Security, Access Control, and Privileges MySQL / General Guides
Most users concentrate on MySQL's databases and tables - after all, that's where most of the action takes place - and they don't usually look deeper to understand how it handles access privileges, passwords, and security. This approach is usually more than adequate for most development activities - unless you happen to be a database administrator whose job involves setting up and securing the databases against unauthorized usage or malicious mischief.