  The data warehousing is becoming increasingly important in terms of strategic
decision making through their capacity to integrate heterogeneous data from
multiple information sources in a common storage space, for querying and
analysis. So it can evolve into a multi-tier structure where parts of the
organization take information from the main data warehouse into their own
systems. These may include analysis databases or dependent data marts. As the
data warehouse evolves and the organization gets better at capturing
information on all interactions with the customer. Data warehouse can track
customer interactions over the whole of the customer's lifetime.
