Query maintenance with hierarchical updates

Abstract

Data warehouse must evolve with changes in the schema, software components, user requirements or organization's business rules. Various authors have proposed different schema evolution operators for various level updates but none of them handled the syntactic and semantic adaptation of queries automatically. Few authors discussed this problem considering few changes in data sources schema and data warehouse structure schema. But they did not deal with the problem due to changes in the hierarchy and its levels in a dimension of the schema. In this paper, we perform what-if analysis for change in the hierarchy and its levels in the data warehouse schema. Queries, views and relations are modeled in a graph annotated with policies to manage the change event. Framework detects the affected part of graph due to change in hierarchical levels and readjusts according to the specified action without making the queries invalid.