Data abstraction and unified data access are the two main concerns that any SOA-based architecture has to address. In the data services discussion, we talked a bit about data abstraction, by first defining data around domain entities and then decorating it with useful methods for data operations. Equally important is the issue of accessing heterogeneous data in a uniform way.
One of the main problems Service Data Objects (SDO) tries to solve is the issue of heterogeneous manner of data management. By data management, we mean data storage as well as operations on data lifecycle. SDO simplifies J2EE data programming model thus giving application developers more time to focus on the business problems.
SDO provides developers an API, the SDO API, and a programming model to access data. This API lets you to work with data from heterogeneous data sources, including RDBMS, entity EJBs, XML sources, web services, EIS data sources using the Java Connector Architecture...