Incremental update to aggregated information for data warehouses over internet

We consider the view maintenance problem in a web-based environment, in which clients query information from databases, stored in the form of materialized data warehouses, without accessing the original data sources. In addition to base data, data warehouses also contain highly aggregated and summarized information suitable for decision support. As changes are made to the data sources, the warehouse views must be updated to reflect a consistent state of the data sources. Recomputation is often too expensive. We describe in this paper an incremental view maintenance method based on the net changes on base table, to maintain the views efficiently in the presence of aggregation and summary information. An architecture of a web-based data warehousing system is described to minimize the workload of the data warehouse. Finally, we develop a prototype application utilizing the new maintenance algorithm and conduct a performance study based on the prototype, comparing it with existing maintenance algorithm.