17th International Workshop on Database and Expert Systems Applications (DEXA'06) (2006)
Sept. 4, 2006 to Sept. 8, 2006
DOI Bookmark: http://doi.ieeecomputersociety.org/10.1109/DEXA.2006.19
Sebastian Link , Massey University, New Zealand
We study inference rules for multivalued dependencies in relational databases with null values (NMVDs). The definition of NMVDs is dependent on the underlying relation schema and this is reflected syntactically by the - complementation rule which is present in all previous axiomatisation of NMVDs. <p>The main result is a sound and complete set of inference rules in which the -axiom is the only inference rule dependent on . This result extends work of Biskup who has provided such an axiomatisation in the absence of null values. It is proven that the set is minimal in a very strong sense. In fact, none of its rules can be omitted without losing the ability to infer all trivial NMVDs.</p>
S. Link, "A Strongly Minimal Axiomatisation of Multivalued Dependencies in Incomplete Database Relations," 17th International Workshop on Database and Expert Systems Applications (DEXA'06)(DEXA), Krakow, Poland, 2006, pp. 537-541.