Functional dependencies in relations with null values
Database dependencies with incomplete information are considered: null values under the no-information interpretation are allowed in the relations, possibly requiring a subset of the relation to be null-free. The definition of functional dependency, the most common integrity constraint for relations without null values, is extended to the new framework, coherently with its motivations. A sound and complete set of inference rules is presented for the implication of functional dependencies.
scientific article; zbMATH DE number 3866614