In this previous post PHPMaster.com introduced you to the concept of "domain models", structures defining how data should be formatted for consistency. In this second part of the series, Alejandro show show to integrate them with a data access layer (DAL) to make them easier to work with.
The phrase may sound like an cheap cliché, I know, but I'm not particularly interested in reinventing the wheel each time I tackle a software problem (unless I need a nicer and faster wheel, of course). In this case, the situation does warrant some additional effort considering we'll be trying to connect a batch of mapping classes to a blog's domain model. Given the magnitude of the endeavor, the idea is to set up from scratch a basic Data Access Layer (DAL) so that domain objects can easily be persisted in a MySQL database, and in turn, retrieved on request through some generic finders.
He includes all the code you'll need to create a (namespaced) database adapter (PDO), the mapping layer to tie the domain models together and using it all in a practical "blog" example with posts, comments and users.