Encyclopedia of Database Systems

2018 Edition
| Editors: Ling Liu, M. Tamer Özsu

Temporal Generalization

  • Christian S. Jensen
  • Richard T. Snodgrass
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-8265-9_1054

Definition

Temporal generalization comes in three guises. Consider a temporal database in which data items are timestamped with valid and transaction time. Temporal generalization occurs when weakening constraints hitherto applied to the timestamps. Used in this sense, temporal generalization is the opposite of temporal specialization.

Next, a temporal relation is generalized when new timestamps are being associated with its tuples. In larger information systems where data items flow between multiple temporal relations, items may accumulate timestamps by keeping their previous timestamps and gaining new timestamps as they are entered into new temporal relations. Thus, a tuple in a particular relation has multiple timestamps: a valid timestamp; a primary transaction timestamp, which records when the tuple was stored in this relation; one or more inheritedtransaction timestamps that record when the tuple was stored in previous relations; and one or more additional timestamps that...

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Recommended Reading

  1. 1.
    Jensen CS, Snodgrass RT. Temporal specialization and generalization. IEEE Trans Knowl Data Eng. 1994;5(6):954–74.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Computer ScienceAalborg UniversityAalborgDenmark
  2. 2.Department of Computer ScienceUniversity of ArizonaTucsonUSA
  3. 3.Dataware VenturesTucsonUSA

Section editors and affiliations

  • Richard T. Snodgrass
    • 1
  • Christian S. Jensen
    • 2
  1. 1.University of ArizonaTucsonUSA
  2. 2.Aalborg UniversityAalborg ØstDenmark