{"title":"Notions of dependency satisfaction","authors":"M. Graham, A. Mendelzon","doi":"10.1145/588111.588142","DOIUrl":null,"url":null,"abstract":"Two notions of dependency satisfaction, consistency and completeness, are introduced. Consistency is the natural generalization of weak satisfaction and seems appropriate when only equality-generating dependencies are given, but disagrees with the standard notion in the presence of tuple-generating dependencies. Completeness is based on the intuitive semantics of tuple-generating dependencies but appears unnatural for equality-generating dependencies. It is argued that neither approach is the correct one, but rather that they correspond to different policies on constraint enforcement, and each one is appropriate in different circumstances. Consistency and completeness of a state are characterized in terms of the tableau associated with the state and in terms of logical properties of a set of first-order sentences associated with the state. A close relation between the problems of testing for consistency and completeness and of testing implication of dependencies is established. The possibility of formalizing dependency satisfaction without using a universal relation scheme is examined.","PeriodicalId":126896,"journal":{"name":"Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems","volume":"35 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"1982-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the 1st ACM SIGACT-SIGMOD symposium on Principles of database systems","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1145/588111.588142","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Two notions of dependency satisfaction, consistency and completeness, are introduced. Consistency is the natural generalization of weak satisfaction and seems appropriate when only equality-generating dependencies are given, but disagrees with the standard notion in the presence of tuple-generating dependencies. Completeness is based on the intuitive semantics of tuple-generating dependencies but appears unnatural for equality-generating dependencies. It is argued that neither approach is the correct one, but rather that they correspond to different policies on constraint enforcement, and each one is appropriate in different circumstances. Consistency and completeness of a state are characterized in terms of the tableau associated with the state and in terms of logical properties of a set of first-order sentences associated with the state. A close relation between the problems of testing for consistency and completeness and of testing implication of dependencies is established. The possibility of formalizing dependency satisfaction without using a universal relation scheme is examined.