Dealing with very large databases is one of the defining challenges in data
mining research and development. Some databases are simply too large (e.g.
, with terabytes of data) to be processed at one time. For efficiency and s
pace reasons, partitioning them into subsets for processing is necessary. H
owever, since the number of item sets in each partitioned data subset can b
e a combinatorial amount and each of them may be a large item set in the or
iginal database, data mining results from these subsets can be very large i
n size. Therefore, the key to data partitioning is how to aggregate the res
ults from these subsets. It is not realistic to keep all results from each
subset, because the rules from one subset need to be verified for usefulnes
s in other subsets. This article presents a model of aggregating associatio
n rules from different data subsets by weighting. In particular, the aggreg
ation efficiency is enhanced by rule selection.