A Novel Decomposition of Multilevel Relations into Single-Level Relations

In this paper we give a new decomposition algorithm that breaks a multilevel relation into single-level relations and a new recovery algorithmwhich reconstructs the original multilevel relation from the decomposed single-level relations. There are several novel aspects to our decomposition and recovery algorithms which provide substantial advantages over previous proposals: 1 Our algorithms are formulated in the context ofanoperationalsemanticsformultilevelrelations, dened here by generalizing the usual update operations of SQL to multilevel relations. 2 Our algorithms, with minor modi cations, can easily accommodate alternative update semantics which have been proposed in the literature. 3 Our algorithms are e cient because recovery is based solely on union-like operations without any use of joins. 4 Our decomposition is intuitively and theoretically simple giving us a sound basis for correctness. In this paper we also argue that some of the alternate update semantics which h...

• Type: Conference
• Year: 1991
• Where: SP
• Authors: Sushil Jajodia, Ravi S. Sandhu
• Keywords: Multilevel Relations, Original Multilevel Relation, Security Privacy, Single-level Relations, SP 1991