Where are we going from here? While no one can predict the future, some trends seem to be underway.
The data warehouse will evolve to support real-time analysis and decision making. Rather than updating the warehouse periodically in batch, when a transaction is committed on the OLTP system, it will become available in the data warehouse, providing the capability of real-time decision making.
This allows the warehouse to be used to support tactical as well as strategic decisions. It enables a credit card company to detect and stop fraud as it happens, a transportation company to reroute its vehicles quickly after an accident has taken place, and an on-line retailer to communicate special offers based on a customer's Web surfing behavior.
One day we may be using a single database for both OLTP and data ware-housing. Oracle is building capabilities into the database that allow a blending of operational and analytical capabilities, many of which are available in Oracle 9i. With this approach it would no longer be necessary to have separate databases for the OLTP, ODS, data warehouse, and data marts. This would eliminate the need for huge volumes of data movement-the extraction, transformation, loading, and replication across these four databases-and reduce the cost and complexity of integrating and managing multiple databases.
Already in Oracle Applications, both OLTP and decision support and reporting are being done in the same Oracle instance using RAC. With Oracle 9i, it is no longer necessary to have a separate relational, OLAP, data mining, or ETL engine. This greatly simplifies the operation and management of the data warehouse infrastructure.
Of course, there is still the need to integrate data from many sources-until they all are stored within one Oracle database.
We've gone from the mainframe in the 1970s to the minicomputers in the 1980s to client/server in the 1990s. Today, Internet computing is the most significant change, because it will slash costs while improving service for every business.
With the Internet it is now possible to deploy business intelligence applications to large, geographically distributed user populations both internally and externally to suppliers and customers.
In this chapter we've taken a look at what gave rise to data warehouses and data marts, some of the highlights of Oracle 9i, some of the many challenges facing warehouse developers, and what we think the future holds. Now it's time to see how we can use all of this technology to build and access our data warehouse.