Using a Kimball data warehouse versus data marts

The starting point of creating a star schema is choosing a process to model. One star model describes one process. A business is always more than a single process. In the theory of Ralph Kimball, a data warehouse is the collection of all star schemas that together describe the entire organization.

There will always be overlap between the individual star schemas you create to model the individual processes. The processes are not completely independent of each other. The sales department sells products that the purchasing department buys. They work with the same products. So, the star schema describing the sales process will have the dimProduct and dimDate dimensions in common with the star for purchasing. They will have different dimensions as well. The star schema for purchasing might have a dimension for suppliers, whereas the sales start schema probably has a dimension for customers.

When you design the dimProduct dimension table...