Web-Based Implementation of Data Warehouse Schema Evolution

Abstract

An organization collects current and historical data for a data warehouse from disparate sources across the organization to support management for making decisions. The data sources change their contents and structure dynamically to reflect business changes or organization requirements, which causes data warehouse evolution in order to provide consistent analytical results. This evolution may cause changes in contents or a schema of a data warehouse. This paper adapts a schema evolution method to address the data warehouse evolution given a data warehouse is built as a multidimensional schema. While existing works have identified and developed schema evolution operations based on conceptual models to enforce schema correctness, only a few have developed software tools to enforce schema correctness of those operations. They are also coupled with specific DBMSs (e.g., SQL Server) and provide limited GUI capability. This paper aims to develop a web-based implementation to support data warehouse schema evolution. It offers all the benefits that Internet browser-based applications provide, by allowing users to design, view, and modify data warehouse schema graphically. This work focuses on evolution operations in dimensional tables, which includes changes in levels, hierarchies, and paths. Schema correctness for each schema evolution operation is ensured by procedural codes implemented in PHP.