Time-Based Operators For Relational Algebra Query Languages

    Authors

    M. A. Bassiouni; M. J. Llewellyn;A. Mukherjee

    Comments

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    Abbreviated Journal Title

    Comput. Lang.

    Keywords

    Historical Databases; Query Languages; Snapshot Databases; Relational; Algebra; Relational; Calculus; Boolean Operators; Historical Databases; Computer Science, Software Engineering

    Abstract

    We present a new approach for historical relational algebra languages based upon generalized logic for Boolean and comparison operators and a temporal modification of the standard relational algebra operators. Historical versions of standard (snapshot) relational algebra operators based upon this generalized logic are presented. The temporal modification employs a logic that operates on sets of value/time-interval pairs and which can be applied to snapshot as well as historical databases. Our emphasis is that the generalized operators can be used to enrich existing historical query languages and to provide an easier and more natural time-based interface. Using the generalized operators, users can express their queries more naturally, succinctly and elegantly. Examples are presented which illustrate that the modified operators offer a good degree of flexibility in expressing different temporal requirements.

    Journal Title

    Computer Languages

    Volume

    19

    Issue/Number

    4

    Publication Date

    1-1-1993

    Document Type

    Article

    Language

    English

    First Page

    261

    Last Page

    276

    WOS Identifier

    WOS:A1993MP94500004

    ISSN

    0096-0551

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