Service-oriented architectures (SOA) are touted as the key to business agility, especially when combined with a model-driven approach. Model-Driven Architecture (MDA) is a well-developed concept that fits well with SOA, but until now it has been a specialized technique that is beyond the scope of most enterprises. Can it be made simpler and more accessible, to become a widely used enabling technology for SOA? With a semantic approach, the answer may well be “Yes”.

The practical benefits of SOA are being increasingly recognized in many industries and applications of Information Technology. For example, Rusty Foreman, Exploration and Production SOA Program Manager for BP, says that the move to so-called "smart" oil and gas fields, with real-time collection and analysis of information driving real-time operational changes, has significant financial benefit, and SOA eliminates the traditional “spaghetti” architecture that requires many interconnected systems to solve a single problem.

Rusty adds that SOA provides a bridge between the business and technical worlds, enabling customers to talk about what they really need. But understanding requirements is just the first step towards business agility. In a truly agile enterprise, the IT infrastructure is aligned with the business structure and it can easily be adapted to meet business needs. The promise of SOA is that this can be achieved by business people who can configure and orchestrate the SOA services.

This implies that the business people have a model of the enterprise services, that they configure the model to reflect business needs, and that this translates directly to the IT implementation, ideally automatically. Such a model-driven approach is well suited to SOA, because the basic architectural building blocks are services, which can be described in a formal language such as the Web Services Definition Language (WSDL). As architecture guru Rakesh Radhakrishnan of Sun Microsystems says, the technologies behind MDA help translate high-level models to an entire IT infrastructure, which allows for the creation of SOA that is decoupled from the lower level platforms and infrastructures.

The Object Management Group (OMG) has defined a number of standards for MDA, covering the definition of models and the exchange of model information. But they are not easy reading. The Meta-Object Facility Specification, which contains the basic model description definition, runs to over 350 pages, and explains in its conceptual overview that “the classical framework for metamodeling is based on an architecture with four metalayers”. It takes a good brain and considerable dedication to get beyond this point. MDA requires intelligent, highly trained architects, and also specialist technology. Good architects are hard to come by, and specialist technology can be expensive. Small wonder that MDA is not widely used in enterprises today.