Functional dependencies on nested attributes: algebraic, logical and topological perspective

We summarise recent results on functional dependencies in nested databases that are generated by record, list, set and multiset constructor. There are three different perspectives from which functional dependencies can be viewed. The algebraic perspective is based on a Brouwerian algebra which is more general than the Boolean powerset algebra from the relational data model. The logical perspective shows that the implication of functional dependencies is equivalent to the implication of Horn clauses. The topological perspective results in an axiomatisation of functional dependencies that is reminiscent of Armstrong´s original axiomatisation for relational databases.