What? Codeignitor is an MVC framework for PHP and is well-known for its ease-of-use, performance and speed.
Why? It is a very popular framework and is probably the best for those new to the medium.
Would you? Yes. It is fast and popular in the Industry.
Codeignitor is a fast and low footprint PHP framework. It is probably the easiest to use and has a good community around it. If you are new to Frameworks, this is probably the best place to start.
Here is a zip file of a simple CRUD app using Codeignitor. It can be used as a building block for much larger applications and is certainly enough to see how Codeignitor works.
You can find the DB config here: /application/config/database.php
Here is the SQL file: