n as data marts contain less data compared with data warehouses, data marts are more
easily understood and navigated.
There are several approaches to building data marts. One approach is to build several
data marts with a view to the eventual integration into a warehouse; another approach is
to build the infrastructure for a corporate data warehouse while at the same time building
one or more data marts to satisfy immediate business needs.
Data mart architectures can be built as two-tier or three-tier database applications. The
data warehouse is the optional first tier (if the data warehouse provides the data for the
data mart), the data mart is the second tier, and the end-user workstation is the third tier,
as shown in Figure 31.3. Data is distributed among the tiers.