On the PHPClasses.org blog today Manuel Lemos has posted a look at ORM - what it is and how you can use it to improve your applications.

Object-Relational Mapping, usually referred as ORM, is a software development approach to treat data stored in relational (SQL) database table records as if they were objects. Basically we can create classes with variables that represent fields of a database table. To insert a table record you need to create an object of the class, assign the variable values, and call a function of the class that takes care of inserting the table record

He illustrates what it is (brief code samples) and some of the approaches that developers have taken to implementing it. He suggests, however, that they should truely be called ROM (Relational Object Mapping) libraries rather than ORM due to the fact that they map an object (the database tables) back in to PHP objects. He finishes with a list of a few ORM resources and libraries including the one that helps power the PHPClasses website, Metastorage.