Making views self-maintainable for data warehousing

A data warehouse stores materialized views over data from one or more sources in order to provide fast access to the integrated data, regardless of the availability of the data sources. Warehouse views need to be maintained in response to changes to the base data in the sources. Except for very simple views, maintaining a warehouse view requires access to data that is not available in the view itself. Hence, to maintain the view, one either has to query the data sources or store auxiliary data in the warehouse. The authors show that by using key and referential integrity constraints, one often can maintain a select-project-join view without going to the data sources or replicating the base relations in their entirety in the warehouse. They derive a set of auxiliary views such that the warehouse view and the auxiliary views together are self-maintainable-they can be maintained without going to the data sources or replicating all base data. In addition, their technique can be applied to simplify traditional materialized view maintenance by exploiting key and referential integrity constraints.