Aggregates in the temporal query language TQuel

Author

Snodgrass, Richard T. ; Gomez, Santiago ; McKenzie, L. Edwin, Jr.

Author_Institution

Dept. of Comput. Sci., Arizona Univ., Tucson, AZ, USA

Volume

5

Issue

5

fYear

1993

fDate

10/1/1993 12:00:00 AM

Firstpage

826

Lastpage

842

Abstract

This paper defines new constructs to support aggregation in the temporal query language TQuel and presents their formal semantics in the tuple relational calculus. A formal semantics for Quel aggregates is defined in the process. Multiple aggregates; aggregates appearing in the where, when, and valid clauses; nested aggregation; and instantaneous, cumulative, moving window, and unique variants are supported. These aggregates provide a rich set of statistical functions that range over time, while requiring minimal additions to TQuel and its semantics. We show how the aggregates may be supported in an historical algebra, both in a batch and in an incremental fashion, demonstrating that implementation is straightforward and efficient

Keywords

query languages; relational databases; temporal databases; TQuel; formal semantics; historical algebra; nested aggregation; statistical functions; temporal database; temporal partitioning; temporal query language; tuple relational calculus; unique variants; valid time; Aggregates; Algebra; Calculus; Computer science; Database languages; Military computing; Proposals; Relational databases; Terminology;

fLanguage

English

Journal_Title

Knowledge and Data Engineering, IEEE Transactions on

Publisher

ieee

ISSN

1041-4347

Type

jour

DOI

10.1109/69.243512

Filename

243512