The solution to these problems is to develop a carefully planned set of architectures. The design of the architectures is a matter of primary strategic importance to the enterprise as a whole because it directly affects the enterprise's ability to seize new business opportunities. The approach that develops systems within an architectural environment is known as "Information Engineering."
The Information Engineering Methodology (IEM) is a rigorous architectural approach to planning, analyzing, designing, and implementing applications within an enterprise. Within the IEM, the enterprise carefully and thoroughly analyzes its information requirements before beginning to build the applications that will support these requirements.
The IEM is a flexible methodology that can be used in different environments and for different purposes. For any given business situation, the IEM defines an appropriate development path. RAD is itself one such path, to be used for rapid development of stand-alone systems, incorporating CASE tools and rapid development techniques.
To overcome the problems that result from the development of isolated
systems, the IE-RAD development path has been defined. IE-RAD integrates
the architectural approach of information engineering with the rapid development
approach of RAD.
The first stage of IE-RAD, Enterprise Modeling (EM), develops the architectures crucial to subsequent development. In this stage, planners develop three architectures - the Information Architecture (functions, entity types, and interactions), the Business Systems Architecture (systems and shared data stores), and the Technical Architecture (hardware, software, and communications) - plus the Information Management Organization (organizational structure and tasks), EM relates closely to the strategic planning of the business as a whole.
The second stage of IE-RAD, Outline Business Area Analysis, narrows the focus and deals only with a subset of the Information Architecture - that is, one business area. During this stage, the enterprise develops a model of the business processes and data requirements of a single business area and assesses the need for new or better systems.
The subsequent stages of IE-RAD narrow the focus still further to a specific system within the business area and within the overall Business Systems Architecture. At this point, a RAD project can begin. The system scope and main requirements have already been defined during EM and BAA, so the RAD project starts at the User Design stage. In such a RAD project, the development coordination function (especially the model administrator and the encyclopedia administrator) is more heavily involved than would be the case in a stand-alone RAD project.
Optimizing systems for the enterprise as a whole may require different actions than optimizing' systems for individual departments. For example, a system optimized for one department may be sub-optimal for the enterprise as a whole. To achieve global optimization, an enterprise needs an enterprise-wide architecture. This takes time to create, but once it is created, systems for local use will often be more effective and will probably be built faster.
Sometimes RAD techniques are used in isolation; at other times, they are used in combination with an information engineering approach incorporating overall architectures. The need to develop systems quickly for competitive advantage is an increasingly powerful motivation to business to move ahead without full-scale development of enterprise architectures. However, the objective of IT communities must be to facilitate as much as possible the integration of separately developed systems. Without this capability, time-critical, competitive opportunities will be lost.
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