Augmented Inherited Multi-Index Structure for Maintenaince of Materialized Path Query Views

Materialized complex object-oriented views are a promising technique for the integration of heterogeneous databases and the development of powerful data warehousing systems. Path query views are virtual classes formed from selection queries that specify a predicate upon the value of an aggregation hierarchy path. The primary diierence between previous work regarding OODB indexing and the eecient implementation of materialized path query views addressed in this paper lies in the nature of their usage. For OODB indexing, query usage is the primary purpose of index structures. Because the materialized view data itself can be used to answer queries, the primary use of index structures with regard to materialized path query views is for the incremental maintenance of views in the face of updates. We have developed an augmented inherited multi-index (AIM) strategy that is specii-cally tailored for the maintenance of materialized path query views. We nd that we can improve update performance by augmenting traditional inherited multi-indices with structured representations of the path queries that use them. This enables us to use class hierarchy relationships to prune the number of aggre-gation paths that must be re-instantiated during update propagation and also to support complex path queries that include cycles.