The data is then warehoused in a relational or multidimensional database. Meanwhile, users and analysts can access and analyze the data with various tools. While the warehouse concept caught on rapidly, questions have arisen lately about whether some warehouse projects have met their goals. Many, if not most, warehouse projects are complex and often take between 18 months and three years to deploy. A lot can happen in that time.
Requirements change, technologies change, corporate strategies shift.
No wonder some users are disappointed by the time big warehouses are finally deployed. It is no surprise, then, that many corporate users are turning to data marts, either as a substitute for date warehousing or as an initial foray into the world of large-scale data analysis. Unlike the all-encompassing enterprise data warehouse, the data mart contains a subset of corporate data that is of value to a specific department. Data marts tend to be much smaller than full-blown warehouses, usually less than 50 gigabytes in size. They are also deployed far more quickly than a warehouse.