In his example code he creates a few new directories in his basic application layout under the "lib" directory to contain the files for the mapper, data access layer and data objects. He uses s simple "user" table with first and last names and an ID to help identify the row.

The User model, mapper and data access object work together to make a simple "getUser" method as easy as creating a new Project_DataMapper_User object and setting up the entity before doing the fetch with a "get" call.