The problem of incomplete information in relational databases
type: Item
instance of: scholarly article
title: The problem of incomplete information in relational databases
zbMATH Open document ID: 0779.68023
author: Gösta Grahne
published in: Lecture Notes in Computer Science
publication date: 1993-01-23T00:00:00Z
review text: In practice it is often the case that the available information is incomplete with respect to the information that is supposed to be recorded in a database. The book of the series ``Lecture Notes in Computer Science'' considers the problems raised by information incompleteness in the context of the relational model. The book consists of five chapters. Chapter 2 reviews the relational model and the operations in a uniform manner. A lattice structure on the set of all relations is imposed. Then several concepts, such as dependency satisfaction and updates can be defined in terms of operations on the lattice. Chapter 3 is a generalization of chapter 2 to the incomplete case, i.e. to sets of sets of relations. The author shows that there are two lattice structures on sets of sets of relations. The operations introduced in Chapter 2 are generalized elementwise to sets of relations, according to the basic intuitiv assumption. Chapter 4 treats the implementation of sets of relations as so called tables. A table is a relation with null values and restrictions on the null values as entries. In Chapter 5 the computational complexity of the introduced algorithms is analyzed, in the pursuit of finding a table class and a set of operations that can be efficiently implemented. In Chapter 6 the author briefly compares the results to other works, and summarizes the significant implications of the previous chapters.
reviewed by: H.-D.Gerhardt
Mathematics Subject Classification ID: 68P15
Mathematics Subject Classification ID: 68-01
zbMATH DE Number: 108266
zbMATH Keywords: relational databases
zbMATH Keywords: incomplete information
zbMATH Keywords: query languages
zbMATH Keywords: data dependencies
zbMATH Keywords: relational model
MaRDI profile type: Publication
description: scientific article; zbMATH DE number 108266