Bi-temporal versioning of schema in temporal data warehouses

Abstract

The temporal design of data warehouse (DW), which is an extension to multidimensional model gives a provision to implement the solution to handle time-varying info in dimensions. The dimension data is time-stamped with valid time (VT) to maintain a complete data history in temporal data warehouses (TDWs). Thus, TDWs manage evolvement of schema over a period of time by using versioning of schemas as well as evolution of data described under various versions of schema. But schema versioning in TDWs has not been covered in full detail. Mainly, the approaches to handle schema versions using valid time were proposed so far. This paper proposes an approach for bitemporal versions of schema in temporal DW model that allows for retroactive and proactive schema modifications and in addition also helps in tracking them.