MANAGING CHANGES TO SCHEMA OF DATA SOURCES IN A DATA WAREHOUSE

In the data warehouse environment, research has not adequately addressed the management of schema changes to source databases. Such changes have important implications. First the metadata used for managing the warehouse is affected by these changes and second, the applications that interact with the source databases may no longer be able to work with the changed schemas. In short, the data in the warehouse may not be consistent with the data and the structure of the source databases. In this paper we examine the implications for managing changes to the schema (or structure) of the operational databases in the context of data warehouses. First, we propose a framework that uses metadata to manage the impact of changes to the schema of source databases on data warehouse(s) that is dependent on these databases. We then examine the implications for managing and propagating these changes to the data transformation applications. We further describe how all of this fits in with the existing architecture of a data warehouse. To the best of our knowledge, this is the first research that examines the issue of schema changes in a data warehouse environment.