R.Kimball’s Approach
Kimball’s Data Warehousing architecture, known as, Data Warehouse Bus (BUS), uses bottom-up technique to create dimensional data marts for specific business process. Dimensional data marts are created using Dimensional Data Modeling, a modeling technique which violates normalization rules and is unique to data warehousing. The data to the data mart is populated from a staging area, where data is at the lowest grain to populate tables. The integration of data marts to create the Data warehouse is achieved by the data warehouse bus in the BUS architecture. Dimensional modeling focuses on ease of end user accessibility and provides a high level of performance to the data warehouse. A popular design used by Kimball for dimensional modeling is the Star Schema, comprising fact tables and dimension tables (Kimball, 2008). The fact table contains very less number of rows and represents the factual or additive values and the dimension table holds the descriptive data for the dimensions. Kimball’s suggests the concept of ‘Conformed Dimensions,’ dimensions which are shared between fact tables, to deal data replication. Kimball recommends a Four-step Dimensional design process for the development of data warehouse with emphasis to keep the granularity of data to the lowest level possible.