Actually, the real value of a distributed data warehouse would be represented on such these cases. Data marts are characterized as their response to the single queries and low cost of their construction. Usually, costs of a distributed data warehouse in a company, which is made of several data marts, are less than half of a centralized data warehouse. Distributed data warehouses, particularly those have an ability to work in a Web environment, are much cheaper and easier in terms of maintenance and also have some significant merits of saving on required equipment for user interface.