Business integration is not an easy task. There are so many technologies and so many ways to represent or interact with data that achieving integration is no easy task. If you take the three aspects of a programming model, which are data, invocation, and composition, and apply some of the new paradigms of a services-based approach, the new programming model for SOA starts to emerge.
First, we see that data is primarily represented by Extensible Markup Language (XML) and is programmed with Service Data Objects (SDOs) or through native XML facilities such as XPath or XSLT (Extensible Stylesheet Language Transformation). Second, service invocation maps to Service Component Architecture (SCA). Finally, composition is embodied in process orchestration using Business Process Execution Language (BPEL). The figure shows the three aspects of this new programming model.
In addition to providing a consistent syntax and mechanism for service invocation, the SCA is the invocation framework that provides a way for developers to encapsulate service implementations in reusable components. It enables developers to define interfaces, implementations, and references in a technology-agnostic way, giving you the opportunity to bind the elements to whichever technology you choose. SCA separates business logic from infrastructure so that application programmers can focus on solving business problems.