In the data warehouse environment, the concept of a materialized view is nowadays common and important in an objective of efficiently supporting OLAP query processing. Materialized views are generally derived from select-project-join of several base relations. These materialized views need to be updated when the base relations change. Since the propagation of updates to the views may impose a significant overhead, it is very important to update the warehouse views efficiently. Though various view maintenance strategies have been discussed so far, they typically require too much access to base relations, resulting in the performance degradation. In this paper we propose an efficient incremental view maintenance strategy called delta propagation that can minimize the total size of base relations accessed by analyzing the properties of base relations. We first define the delta expression and a delta propagation tree which are core concepts of the strategy. Then, a dynamic programming algorithm that can find the optimal delta expression are proposed. We also present various experimental results that show the usefulness and efficiency of the strategy.
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