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Snapshot Semantics for Temporal Multiset Relations




Snapshot semantics is widely used for evaluating queries over temporal data: temporal relations are seen as sequences of snapshot relations, and queries are evaluated at each snapshot. In this work, we demonstrate that current approaches for snapshot semantics over interval-timestamped multiset relations are subject to two bugs regarding snapshot aggregation and bag difference. We introduce a novel temporal data model based on K-relations that overcomes these bugs and prove it to correctly encode snapshot semantics. Furthermore, we present an efficient implementation of our model as a database middleware and demonstrate experimentally that our approach is competitive with native implementations.


  author = {Dign\"{o}s, Anton and Glavic, Boris and Niu, Xing and B\"{o}hlen, Michael H. and Gamper, Johann},
  journal = {Proceedings of the VLDB Endowment},
  keywords = {Temporal Databases; Annotations},
  longversionurl = {https://arxiv.org/pdf/1902.04938},
  reproducibility = {https://github.com/IITDBGroup/2019-PVLDB-Reproducibility-Snapshot-Semantics-For-Temporal-Multiset-Relations},
  projects = {Snapshot Semantics for Temporal Databases},
  number = {6},
  pages = {639--652},
  pdfurl = {http://www.vldb.org/pvldb/vol12/p639-dignoes.pdf},
  title = {{Snapshot Semantics for Temporal Multiset Relations}},
  venueshort = {PVLDB},
  volume = {12},
  year = {2019}


Snapshot Semantics for Temporal Multiset Relations Anton Dignös, Boris Glavic, Xing Niu, Michael H. Böhlen and Johann Gamper Proceedings of the VLDB Endowment. 12, 6 (2019) , 639–652.