Mutual dependencies and some results on undecomposable relations
Jean‐Marie Nicolas · Very Large Data Bases · 1978
In this paper the new concept of mutual dependency in data base relations is introduced. Mutual dependency appears as a generalization of functional and multivalued ones. Furthermore, it provides a necessary and sufficient condition for a relation to be nonloss decomposable into three of its projections. Then, attention is paid to more general decompositions and a necessary and sufficient condition for a relation to be undecomposable is proven.