Attribute-Oriented Knowledge Discovery in Rough Relational Databases

The rough relational database model was developed for the management of uncertainty in relational databases. A particular type of knowledge discovery, attribute oriented induction of rules from generalized data is described in this paper. Rough Relational Databases In rough sets (Pawlak 1984) an approximation space is defined on some universe U by defining some equivalence relation that partitions the universe into equivalence classes called elementary sets, based on some definition of ‘equivalence ’ as it relates to the application domain. Any finite union of these elementary sets is called a definable set. A rough set X U, however, can be defined in terms of the definable sets in terms of its lower (RX) and upper ( R X) approximation regions: RX = {x Ӈ U |[x]