Francois Zeninotto has posted a comparison of three different ORM (Object Relational Mapping) layers for PHP - Propel, Doctrine and sfPropelFinder (the last being a plugin of the symfony framework).

When it comes to ORMs, it's all a matter of preference. Is it, really? This post compares side-by-side the code required to perform some simple operations with three OO database requesting API. The purpose is to demonstrate that productivity, and not only style, can vary a lot depending on the ORM you choose.

He's worked up a long list of examples including methods to:

• Retrieving an article by its primary key
• Retrieving the latest 5 articles
• Retrieving articles based on a complex AND/OR clause
• Retrieving articles authored by people of a certain group
• Retrieving an article and its category by the article primary key
• Retrieving articles and hydrating their author object and the author group

Each one comes with their own (usually simple) code. His conclusions point out different "bests" of each - like sfPropelFinder being the "most magic" and that some of the limits of Propel are very frustrating.