Data Warehousing - Data Marts
A data mart is a subject-or application-specific multidimensional schema build on the top of an Enterprise Data Warehouse.
Data marts are designed for a particular line of business and is an aggregation layer.
Data marts contain dimensional data (dimensions and facts). Facts can contain either atomic data and, if necessary, summarized data.
Data marts are designed and tuned for online analytical processing (OLAP) queries.
Type of data mart
- Star Schema (Physical table on a relational Database)
- Virtualized Star Schema (View on a relational Database)
When not virtualized, it must only store rolling history (ie limited history – not the entire history that is contained in the EDW).