Ronald Fagin
ACM Transactions on Database Systems (TODS)
A new type of dependency, which includes the well-known functional dependencies as a special case, is defined for relational databases. By using this concept, a new (“fourth”) normal form for relation schemata is defined. This fourth normal form is strictly stronger than Codd's “improved third normal form” (or “Boyce-Codd normal form”). It is shown that every relation schema can be decomposed into a family of relation schemata in fourth normal form without loss of information (that is, the original relation can be obtained from the new relations by taking joins). © 1977, ACM. All rights reserved. © 1977, ACM. All rights reserved.
Ronald Fagin
ACM Transactions on Database Systems (TODS)
Joseph Y. Halpern, Ronald Fagin
PODC 1985
Ronald Fagin, Joseph Y. Halpern, et al.
Annals of Pure and Applied Logic
Ronald Fagin, Joseph Y. Halpern
Journal of the ACM