dc.contributor.author Grahne, Gosta en_US dc.contributor.author Raiha, Kari-Jouko en_US dc.date.accessioned 2007-04-23T17:09:37Z dc.date.available 2007-04-23T17:09:37Z dc.date.issued 1985-05 en_US dc.identifier.citation http://techreports.library.cornell.edu:8081/Dienst/UI/1.0/Display/cul.cs/TR85-682 en_US dc.identifier.uri https://hdl.handle.net/1813/6522 dc.description.abstract Acyclic database schemes have attracted much interest because of the nice properties enjoyed by such schemes. Recently some new acyclicity conditions that are strictly stronger than the normal $\alpha$-acyclicity have been introduced by Fagin. Because of increased requirements, the database schemes in the new classes have some further useful properties that are not shared by $\alpha$-acyclic schemes. Therefore the new classes have practical relevance. A database designer may work in terms of attribute sets and data dependencies, and not only in terms of database schemes. Thus it is important to have a characterization for the acyclic schemes of various degree in terms of data dependencies. For $\alpha$-acyclic schemes such a characterization exists, but for the new classes the question has been open. In this paper we provide characterizations for $\beta$-, $\gamma$- and Berge-acyclic database schemes. The characterizations can be stated in a simple form: thus they should be useful for the database designer. en_US dc.format.extent 1994377 bytes dc.format.extent 989514 bytes dc.format.mimetype application/pdf dc.format.mimetype application/postscript dc.language.iso en_US en_US dc.publisher Cornell University en_US dc.subject computer science en_US dc.subject technical report en_US dc.title Characterizations for Acyclic Database Schemes en_US dc.type technical report en_US
﻿