Data Mart in Data warehouse
A data mart is a special purpose subset of a company’s enterprise data used by a particular department, function, or application. Often, these single-subject area data marts contain data that was aggregated or transformed in some way to better handle the requests of a specific user community. Vendors implement data marts using different architectures:
- Independent data marts – Created directly from operational systems to an individual data store.
- Dependent data marts – Created from detail data in the data warehouse. It still requires movement and transformation of data, but may provide better performance for some specific user queries.
- Logical data marts – Existing parts of the data warehouse, not separate physical structures. Because in theory the data warehouse contains the detail data of the entire enterprise, a logical data mart would then provide the specific information for a specific user community. With the proper technology, this can be an ideal way to remove the need for massive data loading and transforming.
Independent and dependent data marts are architectures endorsed by other database vendors and tend to be associated with higher maintenance costs for physically moving and maintaining the data, inconsistent data (and resulting inconsistent decisions), and indirect ways to get the complete picture of the data. The Teradata Database is ideal for the logical data mart environment, where different user communities view subsets of a single repository of enterprise data.