Indexing valid time databases via B+-trees

We present an approach, named MAP21, which uses standard B+-trees to provid e efficient indexing of valid time ranges. The MAP21 approach is based on m apping one dimensional ranges to one dimensional points where the lexicogra phical order among the ranges is preserved. The proposed approach may emplo y more than one tree, each indexing a disjoint subset of the indexed data. When compared to the Time Index and the R*-tree we show that MAP21's perfor mance is comparable to or better than those, depending on the type of query . In terms of storage, MAP21's structure was less than 10 percent larger th an the R*-tree's and much smaller than the Time Index's. The main contribut ion of this paper though, is to show that standard B+-trees, available in v irtually any DBMS, can be used to provide an efficient temporal index.