An EDW is composed of multiple subject areas, such as finance, human resources, marketing, sales, manufacturing, etc. (See figure 1.0). In a top down scenario, the entire EDW is architected, and then a small slice of a subject area is chosen for construction (see figure 1.1). Subsequent slices are constructed, until the entire EDW is complete (see figure 1.2). Complete EDW systems take 3-4 years for construction on average and typically cost $6-8 million (US$) for a mid size organization (based on
multiple industry surveys), large global organizations should expect to spend $20-80 million to build the initial EDW system, which is most likely to be a FDW architecture.