Designing access methods for bitemporal databases

TLDR

Bitemporal databases, which support valid and transaction time dimensions, more accurately represent reality than conventional databases by accounting for each time dimension’s properties. The study investigates efficient access method design for bitemporal databases and proposes partial‑persistence and double‑tree approaches. Partial‑persistence transforms bitemporal queries into partial‑persistence problems, while double‑tree treats each object as two intervals and partitions them by transaction‑time endpoint, and both are benchmarked against a single‑rectangle multidimensional method. Experimental results show that partial‑persistence delivers the best overall performance, particularly for transaction timeslice queries, whereas double‑tree offers a viable off‑the‑shelf alternative.

Abstract

By supporting the valid and transaction time dimensions, bitemporal databases represent reality more accurately than conventional databases. The authors examine the issues involved in designing efficient access methods for bitemporal databases, and propose the partial-persistence and the double-tree methodologies. The partial-persistence methodology reduces bitemporal queries to partial persistence problems for which an efficient access method is then designed. The double-tree methodology "sees" each bitemporal data object as consisting of two intervals (a valid-time and a transaction-time interval) and divides objects into two categories according to whether the right endpoint of the transaction time interval is already known. A common characteristic of both methodologies is that they take into account the properties of each time dimension. Their performance is compared with a straightforward approach that "sees" the intervals associated with a bitemporal object as composing one rectangle, which is stored in a single multidimensional access method. Given that some limited additional space is available, the experimental results show that the partial-persistence methodology provides the best overall performance, especially for transaction timeslice queries. For those applications that require ready, off-the-shelf, access methods, the double-tree methodology is a good alternative.