The interaction of integrity constraints in an information system

摘要

Four families of integrity constraints in a relational database have been investigated: the functional dependency, the decomposition, the cross, and the inclusion. For each family, a complete set of inference rules is presented. Also, a necessary and sufficient condition for a constraint to be a consequence of other constraints of the same family is proved, using the duality between crosses and decompositions. This condition is applied and a new algorithm is presented to solve the membership problem for the decompositions.