Long-Term Evolution of a Conceptual Schema

Enterprises need data resources that are stable and at the same time flexible to support current and new ways of doing business. However, there is a lack of understanding how flexibility of a Conceptual Schema design is demonstrated in its evolution over time. This case study outlines the evolution of a highly integrated Conceptual Schema in its business environment. A gradual decline in schema quality is observed: size and complexity of the schema increase, understandability and consistency decrease. Contrary to popular belief, it is found that changes arent driven only by accepted causes like new legislation or product innovation. Other change drivers are identified like error correction, changing perceptions of what the information need of the business is and elimination of derived data. The case shows that a real Conceptual Schema is the result of objective design practices as well as the product of negotiation and compromise with the user community.