Volume 6 Number 1 (Jan. 2011)
Home > Archive > 2011 > Volume 6 Number 1 (Jan. 2011) >
JSW 2011 Vol.6(1): 3-9 ISSN: 1796-217X
doi: 10.4304/jsw.6.1.3-9

Data Exchange: Algorithm for Computing Maybe Answers for Relational Algebra Queries

S. M. Masud Karim
Computer Science and Engineering Discipline, Khulna University, Khulna 9208, Bangladesh

Abstract—The concept of certain answers is usually used in the definition of the semantics of answering queries in data exchange. But as certain answers are defined as a relation without null values, the approaches for answering queries over databases do not always lead to semantically correct answer. In order to obtain all possible semantically correct answers, maybe answers have been considered along with certain answers. In this paper, an algorithm is presented that produces semantically correct maybe answers to simple relational algebra queries over target schemas of data exchange under the closed world assumption. As there may be infinitely many maybe answers, sophisticated and restricted representation techniques are used to represent them compactly. Then using the compact representation, an algorithm to compute possible (i.e., maybe) answers incrementally is designed. Finally the algorithm is implemented for a fragment of relational algebra.

Index Terms—close world assumption, data exchange, maybe answers, query answering.


Cite: S. M. Masud Karim, "Data Exchange: Algorithm for Computing Maybe Answers for Relational Algebra Queries," Journal of Software vol. 6, no. 1, pp. 3-9, 2011.

General Information

ISSN: 1796-217X (Online)
Frequency:  Bimonthly (Since 2020)
Editor-in-Chief: Prof. Antanas Verikas
Executive Editor: Ms. Yoyo Y. Zhou
Abstracting/ Indexing: DBLP, EBSCO, Google Scholar, ProQuest, INSPEC(IET), ULRICH's Periodicals Directory, WorldCat, etc
E-mail: jsw@iap.org
  • Apr 26, 2021 News!

    Vol 14, No 4- Vol 14, No 12 has been indexed by IET-(Inspec)     [Click]

  • Jun 22, 2020 News!

    Papers published in JSW Vol 14, No 1- Vol 15 No 4 have been indexed by DBLP     [Click]

  • Sep 13, 2021 News!

    The papers published in Vol 16, No 6 have all received dois from Crossref    [Click]

  • Jan 28, 2021 News!

    [CFP] 2021 the annual meeting of JSW Editorial Board, ICCSM 2021, will be held in Rome, Italy, July 21-23, 2021   [Click]

  • Sep 13, 2021 News!

    Vol 16, No 6 has been published with online version     [Click]