Journal of Intelligent Information Systems

, Volume 41, Issue 2, pp 285–311 | Cite as

Querying now-relative data

  • Luca Anselma
  • Bela Stantic
  • Paolo TerenzianiEmail author
  • Abdul Sattar


Now-relative temporal data play an important role in most temporal applications, and their management has been proved to impact in a crucial way the efficiency of temporal databases. Though several temporal relational approaches have been developed to deal with now-relative data, none of them has provided a whole temporal algebra to query them. In this paper we overcome such a limitation, by proposing a general algebra which is parametrically adapted to cope with the relational approaches to now-relative data in the literature, i.e., MIN, MAX, NULL and POINT approaches. Besides being general enough to provide a query language for several approaches in the literature, our algebra has been designed in such a way to satisfy several theoretical and practical desiderata: closure with respect to representation languages, correctness with respect to the “consensus” BCDM semantics, reducibility to the standard non-temporal algebra (which involves interoperability with non-temporal relational databases), implementability and efficiency. Indeed, the experimental evaluation we have drawn on our implementation has shown that only a slight overhead is added by our treatment of now-relative data (with respect to an approach in which such data are not present).


Temporal relational databases Now-related data Querying bitemporal data Algebraic operators Experimental evaluation 


  1. Agesen, M., Bohlen, M., Poulsen, L., Torp, K. (2001). A split operator for now-relative bitemporal databases. In Proceedings of the 17th international conference on data engineering, 2001 (pp. 41–50).Google Scholar
  2. Bohlen, M.H., Snodgrass, R.T., Soo, M.D. (1996). Coalescing in Temporal Databases. In Proceedings of the 22nd VLDB conf (pp. 180–190).Google Scholar
  3. Clifford, J., Dyreson, C., Isakowitz, T., Jensen, C.S., Snodgrass, R.T. (1997). On the semantics of “Now” in databases. ACM Transactions on Database Systems (TODS), 22(2), 171–214.CrossRefGoogle Scholar
  4. Codd, E.F. (1972). Relational completeness of data base sublanguages. In R. Rustin (Ed.), Database systems (pp. 65–98). San Jose: Prentice Hall and IBM Research Report RJ 987.Google Scholar
  5. Creem, K.N. (2005). A comparison of approaches to modeling now in bitemporal databases. In Proceedings of the 21st computer science seminar. Hartford, USA.Google Scholar
  6. Dyreson, C.E. (2003). Temporal coalescing with now granularity, and incomplete information. In Proceedings of the 2003 ACM SIGMOD international conference on management of data, SIGMOD ’03 (pp. 169–180). New York: ACM.CrossRefGoogle Scholar
  7. Dyreson, C.E., Jensen, C.S., Snodgrass, R.T. (2009). Now in temporal databases. In L. Liu, & M. Özsu (Eds.), Encyclopedia of database systems (pp. 1920–1924). USA: Springer.Google Scholar
  8. Fenk, R., Markl, V., Bayer, R. (2002). Interval processing with the UB-tree. In Proceedings of the 2002 international symposium on database engineering and applications (pp. 12–22).Google Scholar
  9. Franzblau, D.S., & Xenakis, G. (2008). An algorithm for the difference between set covers. Discrete Applied Mathematics, 156(10), 1623–1632.MathSciNetCrossRefzbMATHGoogle Scholar
  10. Hellerstein, J., Koutsupias, E., Papadimitriou, C. (1997). On the analysis of indexing schemes. In Proceedings of the 16th ACM SIGACT-SIGMOD-SIGART symposium on principles of database systems.Google Scholar
  11. Jensen, C.S., & Lomet, D.B. (2001). Transaction timestamping in (temporal) databases. In Proceedings of the international conference on very large data bases (pp. 441–450).Google Scholar
  12. Jensen, C.S., & Snodgrass, R.T. (1996). Semantics of time-varying information. Information Systems, 21(4):311–352.CrossRefGoogle Scholar
  13. Jensen, C.S., & Snodgrass, R. (1999). Temporal data management. IEEE Transactions on Knowledge and Data Engineering, 11(1), 36–44.CrossRefGoogle Scholar
  14. Kriegel, H., Pötke, M., Seidl, T. (2000). Managing intervals efficiently in object-relational databases. In Proceedings of the 26th international conference on very large databases (pp. 407–418).Google Scholar
  15. Liu, L., & M.T. Özsu (eds) (2009). Encyclopedia of Database Systems. USA: Springer.CrossRefzbMATHGoogle Scholar
  16. Lomet, D., Hong, M., Nehme, R., Zhang, R. (2008). Transaction time indexing with version compression. Proceedings of the VLDB Endowment, 1(1), 870–881.Google Scholar
  17. Mao, C., Ma, H., Tang, Y., Yao, L. (2011). Temporal data model and temporal database systems. In Y. Tang, X. Ye, N. Tang (Eds.), Temporal information processing technology and its application (pp. 69–89). Berlin, Heidelberg: Springer.Google Scholar
  18. Melton, J., & Simon, A.R. (2002). SQL:1999—Understanding relational language components. San Mateo: Morgan Kaufmann.Google Scholar
  19. McKenzie, J.L.E., & Snodgrass, R.T. (1991). Evaluation of relational algebras incorporating the time dimension in databases. ACM Computing Surveys (CSUR), 23(4), 501–543.CrossRefGoogle Scholar
  20. Nguyen-Dinh, L.-V., Aref, W.G., Mokbel, M.F. (2010). Spatio-temporal access methods: part 2 (2003—2010). IEEE Data Engineering Bulletin, 33(2), 46–55.Google Scholar
  21. Ozsoyoglu, G., & Snodgrass, R. (1995). Temporal and real-time databases: a survey. IEEE Transations on Knowlege and Data Engineering, 7(4), 513–532.CrossRefGoogle Scholar
  22. Šaltenis, S., & Jensen, C.S. (2002). Indexing of now-relative spatio-bitemporal data. VLDB Journal, 11(1), 1–16.CrossRefGoogle Scholar
  23. Shichao Zhang, C.Z., & Qin, Z. (2003). Modeling temporal semantics of data. Asian Journal of Information Technology, 2(1), 25–35.CrossRefGoogle Scholar
  24. Snodgrass, R.T. (1995). The TSQL2 temporal query language. Kluwer Academic.Google Scholar
  25. Stantic, B., Sattar, A., Terenziani, P. (2009). The point approach to represent it now in bitemporal databases. Journal of Intelligent Information Systems, 32(3), 297–323.CrossRefGoogle Scholar
  26. Stantic, B., Terry, J., Topor, R.W., Sattar, A. (2010). Indexing temporal data with virtual structure. In Advances in databases and information systems—ADBIS (pp. 591–594).Google Scholar
  27. Stantic, B., Thornton, J., Sattar, A. (2003). A novel approach to model NOW in temporal databases. In Proceeding of the 10th international symposium on temporal representation and reasoning (TIME-ICTL 2003) (pp. 174–181). Cairns.Google Scholar
  28. Stantic, B., Topor, R.W., Terry, J., Sattar, A. (2010). Advanced indexing technique for temporal data. Computer Science and Information Systems, 7(4), 679–703.CrossRefGoogle Scholar
  29. Tansel, A.U., Clifford, J., Gadia, S., Jajodia, S., Segev, A., Snodgrass, R. (Eds.) (1993). Temporal databases: theory, design, and implementation. Redwood City: Benjamin-Cummings.Google Scholar
  30. Torp, K., Jensen, C.S., Bohlen, M. (1999). Layered implementation of temporal DBMS concepts and techniques. A TimeCenter Technical Report TR-2.Google Scholar
  31. Torp, K., Jensen, C.S., Böhlen, M.H. (1997). Layered temporal dbms: concepts and techniques. In Proceedings of the 5th international conference on database systems for advanced applications (DASFAA) (pp. 371–380). Singapore: World Scientific.Google Scholar
  32. Torp, K., Jensen, C.S., Snodgrass, R.T. (2000). Effective timestamping in databases. VLDB Journal: Very Large Data Bases, 8(3–4), 267–288.CrossRefGoogle Scholar
  33. Torp, K., Jensen, C.S., Snodgrass, R.T. (2004). Modification semantics in now-relative databases. Information Systems, 29(8), 653–683.CrossRefGoogle Scholar
  34. Tsotras, V., & Kumar, A. (1996). Temporal database bibliography update. ACM Sigmod Record, 25(1), 41–51.Google Scholar

Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  • Luca Anselma
    • 1
  • Bela Stantic
    • 2
  • Paolo Terenziani
    • 3
    Email author
  • Abdul Sattar
    • 2
    • 4
  1. 1.Dipartimento di InformaticaUniversità di TorinoTorinoItaly
  2. 2.Institute for Integrated and Intelligent SystemsGriffith UniversityBrisbaneAustralia
  3. 3.Dipartimento di InformaticaUniversità del Piemonte Orientale “Amedeo Avogadro”AlessandriaItaly
  4. 4.National ICT AustraliaBrisbaneAustralia

Personalised recommendations