Query Plans for Conventional and Temporal Queries Involving Duplicates and Ordering G. Slivinskas, C. Jensen, and R. Snodgrass   View Paper (PDF)   Return to Spatial and Temporal Data Abstract Most real-world database applications contain a substantial portion of time-referenced, or temporal, data. Recent advances in temporal query languages show that such database applications could benefit substantially from built-in temporal support in the DBMS. To achieve this, temporal query representation, optimization, and processing mechanisms must be provided. This paper presents a general, algebraic foundation for query optimization that integrates conventional and temporal query optimization and is suitable for providing temporal support both via a stand-alone temporal DBMS and via a layer on top of a conventional DBMS. By capturing duplicate removal and retention and order preservation for all queries, as well as coalescing for temporal queries, this foundation formalizes and generalizes existing approaches. DiSC'01 Copyright ©2002 ACM Inc.