SCA, SDO and DAS

Times from times I have read about standards like SCA and SDO in a SOA environment. This article was written by three IBM guys and it presents an overview of SDA and SDO.

Apache Tuscany project aims to create a infrastructure that simplifies the development of SOA-based systems. This project uses independent technology and standard that together provide:

• SCA: Service Component Architecture (SCA) enables composition of service networks through assembly of existing and new services;
• SDO: Service Data Object (SDO) provides a uniform interface for handling different forms of data, including XML documents, that can exist in a network of services and provides the mechanism for tracking changes;
• DAS: Data Access Service (DAS) provides a simple SDO interface to relational databases.

(image from Apache Tuscany website)

These specifications can be found at OSOA web site and Apache Tuscany provides input for them.

Here the SCA and SDO definitions from Tucany Project:

- SCA: "SCA provides developers with a simple, business-oriented, model for creating systems based on a service oriented architecture. It manages infrastructure complexities such as transactions, security and reliable messaging and frees the developer to focus on providing business function. The solutions developed using SCA can be changed declaratively to alter infrastructure capabilities or application configuration properties to meet changing business requirements. For example, infrastructure capabilities such as security policies may change from one environment to another and can be changed without the need for re-implementation. Application configuration may also be changed in this way, for example, the currency quoted by a stock quote feed may be changed though the SCA configuration mechanism."

- SDO: "Service Data Objects simplify and unify SOA data access architecture and code in a heterogeneous environment. SDO is programming language neutral. Within Tuscany it is being implemented in Java and in C++."