LESS COSTLY CONSTRAINTS CHECKING FOR JOIN DEPENDENCY.

Abstract

A set of n tuples in a relation of a relational database design is tested upon the constraints of the join dependency. Some constraint equalities are found to be redundant. To remove this superfluity, the universe of attibutes is partitioned into n disjoint sets and a new notation of join dependency is introduced. The checking time in each run of n tuples is significantly reduced by a factor of (n minus 1)/2 when n greater than 3. The result of less costly constraints checking is of great importance for a large number of tuples in a relation.