Towards an abstract theory of dependency constraints in relational databases

Abstract We introduce the notion of an FD system on a semilattice as a generalization of the concept of a closed set of functional dependencies, and we study lattice-theoretical properties of those objects. The notion of a table as an abstraction of relations of relational databases is also considered, and a generalization of relational algebra is presented; this offers a better perspective on the role played by Armstrong's relations. Finally, an application of this algebraic approach to dynamic databases is included.