Updated: Jul 1, 2020
What is data mart ?
A data mart (DM) can be seen as a small data warehouse, covering a certain subject area and offering more detailed information about the market (or department) in question..
A data mart can be created in two ways:
Capturing data directly from transnational systems, each data mart is seeking the relevant information for its market;
Capturing data from all transnational systems in a central data warehouse, which in turn feed all data marts.
The first option will provide a faster data mart, but without considering the cross-information between the other subject areas. The second option tends to be more efficient, but it will require more time to deliver results.
A top-down perspective considers that a full, centralized DW should be developed before parts of it, summarized, can be derived in the form of Data Marts. On the other side, a bottom-up perspective considers that a DW can be composed from previously developed data marts.
Difference between Data warehouse and Data mart: