Practical Approach to Selecting Data Warehouse Views Using Data Dependencies

Materialized views in data warehouses are typically complicated, making the maintenance of such views difficult. However, they are also very important for improving the speed of access to the information in the data warehouse. So, the selection of materialized views is crucial to the operation of the data warehouse both with respect to maintenance and speed of access. Most research to date has treated the selection of materialized views as an optimization problem with respect to the cost of view maintenance and/or with respect to the cost of queries. In this paper, we consider practical aspects of data warehousing. We identify problems with the star and snowflake schema and suggest solutions. We also identify practical problems that may arise during view selection and suggest heuristics based on data dependencies and access patterns that can be used to measure if one set of views is better than another set of views, or used to improve a set of views.