Search engines such alta vista and lycos attempt warehouse the entire web

warehousing is especially important in industry today because of a need for enterprises to gather all of their information into a single place for in-depth analysis, and the desire to decouple such analysis from their OLTP systems. Since decision support often is the goal of data warehousing, clearly warehouses may be tuned for decision support, and perhaps vice versa.

In its simplest form, data warehousing can be considered as an example of asynchronous replication, in which copies are updated relatively infrequently (see [Ramakrishnam 1998] for more discussion). However, a more advanced implementation of data warehousing would store summary data or other kind of information derived from the source data. In other words, a data warehouse stores materialized views (plus some local relations if needed).

© 2000 by CRC Press LLC

middleware engine differ, depending on whether a global catalog or directory exists), and

Middleware

Warehouse

© 2000 by CRC Press LLC