Some Remarks on Functional Dependencies in Relational Datamodels

  Vu Duc Thi Le Thi Thanh

Abstract:

  The concept of minimal family is introduced. We prove that this family and family of functional dependencies determine each other uniquely. A characterization of this family is presented.

 We show that there is no polynomial time algorithm finding a minimal family from a given relation scheme. We prove that the time complexity of finding a minimal family from a given relation is exponential in the number of attributes.

  Key Words and Phrases: relation, relational datamodel, functional dependency, relation scheme, closure, closed set, minimal generator, key, minimal key, antikey.

 Gyenizse Pal 1996. Szeptember 4. Szerda 11:29:58 MET DST