Data Mart

Data Mart

When we restrict the scope of a data warehouse to a sub set of business process or subject area we call it a Data Mart. Data Marts can be stand-alone entities, built from warehouses or be used to build warehouse.
     

1. Stand-Alone Data Marts – These are single subject areas data warehouses. Stand alone data marts could cause many stove-pipe/silo data marts in the future. 

2. Data Marts fed from Enterprise Data Warehouses (Top-Down). This is the Top-Down strategy suggested by Bill Inman. Here we build an enterprise data warehouse (EDW) hosting data for multiple subject areas. From the EDW we build subject area specific data marts. 

3. Data Marts building Data Warehouses (Bottom-Up). This is the Bottom-Up strategy suggested by Ralph Kimball. Here we build subject area specific data marts first, keeping in mind the shared business attributes (called conformed dimensions). Using the conformed dimensions we build a warehouse.