Database Systems (TODS)


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ACM Transactions on Database Systems (TODS), Volume 4 Issue 4, Dec. 1979

Extending the database relational model to capture more meaning
E. F. Codd
Pages: 397-434
DOI: 10.1145/320107.320109
During the last three or four years several investigators have been exploring “semantic models” for formatted databases. The intent is to capture (in a more or less formal way) more of the meaning of the data so that database design...

Efficient optimization of a class of relational expressions
A. V. Aho, Y. Sagiv, J. D. Ullman
Pages: 435-454
DOI: 10.1145/320107.320112
The design of several database query languages has been influenced by Codd's relational algebra. This paper discusses the difficulty of optimizing queries based on the relational algebra operations select, project, and join. A matrix, called a...

Testing implications of data dependencies
David Maier, Alberto O. Mendelzon, Yehoshua Sagiv
Pages: 455-469
DOI: 10.1145/320107.320115
Presented is a computation method—the chase—for testing implication of data dependencies by a set of data dependencies. The chase operates on tableaux similar to those of Aho, Sagiv, and Ullman. The chase includes...

Pipelining: a technique for implementing data restructurers
Barron C. Housel
Pages: 470-492
DOI: 10.1145/320107.320118
In the past several years much attention has been given to the problem of data translation. The focus has been mainly on methodologies and specification languages for accomplishing this task. Recently, several prototype systems have emerged, and...

Theseus—a programming language for relational databeses
Jonathan E. Shopiro
Pages: 493-517
DOI: 10.1145/320107.320121
Theseus, a very high-level programming language extending EUCLID, is described. Data objects in Theseus include relations and a-sets, a generalization of records. The primary design goals of Theseus are to facilitate the writing of...

Design of a balanced multiple-valued file-organization scheme with the least redundancy
Sumiyasu Yamamoto, Shinsei Tazawa, Kazuhiko Ushio, Hideto Ikeda
Pages: 518-530
DOI: 10.1145/320107.320123
A new balanced file-organization scheme of order two for multiple-valued records is presented. This scheme is called HUBMFS2 (Hiroshima University Balanced Multiple-valued File-organization Scheme of order two). It is...

On searching transposed files
D. S. Batory
Pages: 531-544
DOI: 10.1145/320107.320125
A transposed file is a collection of nonsequential files called subfiles. Each subfile contains selected attribute data for all records. It is shown that transposed file performance can be enhanced by using a proper strategy to process queries....

Comments on “Process synchronizaiton in databases systems”
Philip A. Bernstein, Marco A. Casanova, Nathan Goodman
Pages: 545-546
DOI: 10.1145/320107.320126