Temporal XML? SQL strikes back

While the introduction of temporal extensions into database standards has proven difficult to achieve, the newly introduced SQL:2003 and XML/XQuery standards have actually enhanced our ability to support temporal applications in commercial database systems. We illustrate this point by discussing three approaches that use temporally grouped representations. We first compare the approaches at the logical level using a common set of queries; then we turn to the physical level and discuss our ArchIS system that supports the three different approaches efficiently in one unified physical implementation. We conclude that the approaches of managing transaction-time information using XML and SQL can be integrated and supported efficiently within the current standards, and claim that the proposed approach can be extended to valid-time and bitemporal databases. 1