Abstract

A view is a derived relation defined in terms of base relations. A view can be materialized by storing its extent in the database. An index can be made of these views and access to materialized view is much faster that recomputing the view from scratch. A Data Warehouse stores large amount of information collected from a different data sources. In order to speed up query processing, warehouse usually contains a large number of materialized views. When the data sources are updated, the views need to be updated. The process of keeping view up to date called as materialize view maintenance. Accessing base relations for view maintenance can be difficult, because the relations may be being used by users. Therefore materialize view maintenance in data warehousing is an important issue. For these reasons, the issue of self-maintainability of the view is an important issue in data warehousing. In this paper we have shown that a materialized view can be maintained without accessing the view itself by materializing additional relations at the data warehouse site. We have developed a cost effective approach to reduce the burden of view maintenance and also proved that proposed approach is optimum as compared to other approaches. Here incremental evaluation algorithm to compute changes to materialized views in relational is presented.