Indexing bitemporal databases as points

Abstract

A bitemporal database supports both the valid and transaction time dimensions. Records in such a database can be viewed as a rectangle in a 2-dimensional space (corresponding to the valid and transaction time dimensions). Hence, a spatial access method can be employed to facilitate speedy retrieval of the database. In this paper, we re-examine the issue of designing efficient access methods for bitemporal databases. In particular, we transform a record into a point in a multi-dimensional space, where the valid time and transaction time are each mapped to a 2-dimensional coordinate. A temporal selection operation can then be implemented as a region search operation. This allows us to tap into the many point access methods that are commercially available without modification. We implemented and evaluated three R-tree based methods on key-range time-slice queries: the naive Point R-tree, the Dual Point R-tree and the Dual Spatial R-tree. Our experimental results show that while the simple Point R-tree is inferior to the Dual Spatial R-tree, the Dual Point R-tree has the best performance of the three.