ORMer is a free, open-source (MIT License) object-relational mapping class written in PHP.
Features
The primary goal is to provide ORM functionality while keeping things easy on the developer. It makes no assumptions about table/field naming conventions and requires minimal configuration (no XML configuration files). For Sqlite2 and MySQL 5.1.x it provides automatic relation discovery through foreign keys.
The class allows additional stipulations when referencing related data (such as the orders associated with a particular customer). See the second line of code in the example below.
References
ORMer Wikipedia(Text) CC BY-SA