XBiT: An XML-Based Bitemporal Data Model

Past research work on modeling and managing temporal information has, so far, failed to elicit support in commercial database systems. The increasing popularity of XML offers a unique opportunity to change this situation, inasmuch as XML and XQuery support temporal information much better than relational tables and SQL. This is the important conclusion claimed in this paper where we show that valid-time, transaction-time, and bitemporal databases can be naturally viewed in XML using temporally-grouped data models. Then, we show that complex historical queries, that would be very difficult to express in SQL on relational tables, can now be easily expressed in standard XQuery on such XML-based representations. We first discuss the management of transaction-time and valid-time histories and then extend our approach to bitemporal histories. The approach can be generalized naturally to support the temporal management of arbitrary XML documents and queries on their version history.