In a post to his site Michelangelo van Dam shows you how to speed up database calls with PDO and iterators in a "no framework" environment.
When you review lots of code, you often wonder why things were written the way they were. Especially when making expensive calls to a database, I still see things that could and should be improved.
When working with a framework, mostly these database calls are optimized for the developer and abstract the complex logic to improve and optimize the retrieval and usage of data. But then developers need to build something without a framework and end up using the basics of PHP in a sub-optimal way.
He points out some of the common issues with a simple approach using just PDO and simple arrays including performance issues. Instead he recommends the use of iterators that wrap a PDO connection and allow for much simpler fetching and iteration of the found results. He includes code examples for a base iterator instance and a way to extend it to get the customized results. He also includes a few benchmarks showing the difference between a foreach loop and this iterator method.