New Closure Operators and Lattice Representations for Multivalued Dependencies and Related Expressions

14th USENIX Security Symposium

Jaume Baixeries ; José Luis Balcázar

Others  :  http://CEUR-WS.org/Vol-162/paper3.pdf
PID  :  50495

来源: CEUR

【 摘 要 】

In Database Theory, Multivalued Dependencies are the main tool to define the Fourth Normal Form and, as such, their inference problem has been deeply studied; two related notions appearing in that study are a syntactical analog in propositional logic and a restriction that maintains to this logic the same relationship as Functional Dependencies do to Horn logic. We present semantic, lattice-theoretic characterizations of such multivalued dependencies that hold in a given relation, as well as similar results for the related notions just mentioned. Our characterizations explain better some previously known facts by providing a unifying framework that is also consistent with the studies of Functional Dependencies.