CodeIgniter is my favorite PHP framework. It’s not only simple to understand and use but it also provides excellent documentation and an amazing community. I’ve built a couple of applications and whenever i needed something the answer was either in the doc files or in the community forums. Earlier today i found this CodeIgniter Cheat Sheet which is actually a summary of the libraries and helpers provided. Handy don’t you think?
If you are starting out with mysql databases or even if you need a point of reference for all the field types available in MySQL there’s a nice and little cheat sheet that lists them with ranges and restrictions.