ACM Transactions on Database Systems

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 can become more ...

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 tableau, ...

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 previous tableau computation methods as ...

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 now the ...

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 well-structured ...

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 assumed that records are ...

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. Analytic ...