Ordered functional dependencies in relational databases

Printed in Great Britain ORDERED FUNCTIONAL DEPENDENCIES IN RELATIONAL DATABASES

We extend the relational data model to incorporate linear orderings into data domains which we call the ordered relational model The conventional Functional Dependencies FDs are examined in the context of ordered relational databases by using the notion of System Ordering Independence SOI which refers to the desirable scenario that the ordering of tuples in a relation is independent of the impl...

Functional Dependencies in Relational Databases : A Lattice

A lattice theoretic approach is developed to study the properties of functional dependencies in relational databases. The particular attention is paid to the analysis of the semilattice of closed sets, the lattice of all closure operations on a given set and to a new characterization of normal form relation schemes. Relation schemes with restrictions on functional dependencies are also studied.

Fuzzy Functional Dependencies in Relational Databases

The work on this paper is an application of fuzzy set theory in relational databases. The authors introduce a new notion of fuzzy functional dependencies (ffd) in relational databases. It is observed that the existing notions of fuzzy functional dependencies (ffd) have a common drawback. Consequently the need for introducing a new type of fuzzy functional dependencies (ffd) is justified, and ex...

Dependencies in Relational Databases

Discovery of functional and approximate functional dependencies in relational databases

This study develops the foundation for a simple, yet efficient method for uncovering functional and approximate functional dependencies in relational databases. The technique is based upon the mathematical theory of partitions defined over a relation’s row identifiers. Using a levelwise algorithm the minimal non-trivial functional dependencies can be found using computations conducted on intege...