Service Data Objects (SDOs) enable PHP applications to work with data from different sources, such as databases and XML files, using a single interface. The PHP implementation of SDO is the first to map SDO to a weakly and dynamically typed scripting environment. The result is a technology which, at its heart provides the same functionality and compatibility as other implementations, but externally present an API that is tailored to the target language.
For more information, see the SDO for PHP white paper.