Framework for query optimization in temporal databases.

摘要

We investigate issues pertaining to query processing of temporal databases in a relational environment. Tuple-versioning of relations is the adopted method of temporal data representation. New operators are necessary in order to exploit the richer semantics of temporal queries. We define four types of temporal joins-- theta-join, time intersection, time union and the event-join. Factors that affect processing strategies are discussed, especially the problem of estimating data selectivity for various temporal operations. Strategies for implementing the temporal equijoin operator are evaluated. 26 refs., 6 tabs. (ERA citation 15:036684)