Enterprise Data Warehousing

Architecture Is Different than Methodology
It is important to recognize that data warehouse architecture identifies component parts, their characteristics, and the relationships among the parts, while methodology identifies the activities that have to be performed and their sequencing. Too often, the architecture and methodology terms are used interchangeably, which creates confusion. The architecture is the end product while a methodology is the process for developing an end product. But while architecture and methodology are different, they should be compatible. It is important to use a methodology that is consistent with the architecture that is being implemented.

Sometimes the hub and spoke architecture (e.g., Corporate Information Factory) is referred to as a top down approach and the bus architecture as bottom up. The reason for this is that the hub and spoke architecture places considerable emphasis on initially putting the infrastructure and processes in place to create an enterprise data warehouse and the bus architecture focuses on delivering a solution that addresses a current business need. These are methodologies rather than architectures because they describe development processes.

Over time, the top down and bottom up approaches have become increasingly similar. Advocates of the top down approach agree on the importance of developing incrementally and delivering early “wins.” The bottom-up proponents recognize the importance of having an enterprise plan for integrating the incrementally developed data marts. As a result, the two methodologies are not as different as many people believe.