Maintaining consistency in partially self-maintainable views at the data warehouse

A data warehouse is a global repository, which stores facts originating from multiple, possibly heterogeneous sources in materialized views. Keeping these views up-to-date incrementally in response to the changes in the source data is referred to as incremental view maintenance. In such a dynamic environment, maintaining the consistency of warehouse is challenging because of the heterogeneity of data sources. The paper presents a scheme for maintaining data consistency at the warehouse. It does so by storing some additional information at the data sources as well as at the data warehouse. We achieve partial self-maintainability of materialized views at the data warehouse by exploiting the already existing key dependencies in the views. We identify the problems in maintaining consistency and present an algorithm that minimizes blocking of sequential updates to be installed in a materialized view at the data warehouse and thus reduces the view maintenance time