Generalized Mutual Dependencies And The Decomposition Of Database Relations

Mutual dependencies have been shown to provide a necessary and sufficient condition for a relation to be decomposable into three of its projections. We generalize the notion of mutual dependency by extending it to any number of sets of attributes and removing some constraints from its original definition. We show that a generalized mutual dependency, together with a set of multivalued dependencies, provide a necessary and sufficient condition for a relation to be decomposable in the general case.