Evolution towards Strategic Applications of Databases through Composite Information Systems

Many important strategic applications involve inter-corporate linkage or intra-corporate integration of information. This requires multiple databases to work together. We refer to this category of information systems as Composite Information Systems (CIS). Migrating from separate systems to a more fully integrated CIS environment is usually a difficult, expensive, and timeconsuming process both due to technical and organizational realities. An evolutionary approach is presented in this paper to meet the challenge. The essence of this approach is captured in four CIS principles: (1) the separation of data from processing; (2) the use of flexible tools; (3) the use of interfaces that facilitate data conversion and communication between processing components and databases; and (4) the explicit recognition of the CIS environment. Based on the principles, we delineate five stages of evolution, which may co-exist: (1) separate systems; (2) virtual-driver; (3) logical separation; (4) physical separation; and (5) specialized functional engine. The opportunities for strategic uses of information technology in organizations are often blocked by the difficulties of getting from the current state to the desired situation. The evolutionary process presented in this paper has been found to be effective in overcoming this problem.