database-normalizationdenormalizationsap-bw

Why are dimension tables denormalized in an InfoCube?


SAP BW class material states that in InfoCubes, dimensions are denormalized.

I understand the benefit of normalized tables.

Why are dimension tables denormalized in an InfoCube?


Solution

  • In a data warehouse, you're trying to get a faster response time.

    The data is loaded one time, and read many times. Therefore, normalization of data is not an advantage in a data warehouse.

    Denormalization is a bit of a misnomer. In a star schema, the data is not normalized. I do understand that some people are referring to the data loading process as denormalization. But, in general, designing a star schema is not a denormalization

    By not normalizing the dimension data, you're improving the response time by increasing the load time and storage space for the data warehouse.