1. In a computer data processing system, a method for clustering data in a database comprising the steps of: a) choosing a cluster number K for use in categorizing the data in the database into K different clusters; b) accessing data records from a database and bringing a data portion into a rapid access memory; c) assigning data records from the data portion to one of the K different clusters and determining a mean of the data records assigned to a given cluster; d) summarizing at least some of the data assigned to the clusters, storing a summarization of the data within the rapid access memory; e) accessing an additional portion of the data records in the database and bringing said additional portion into the rapid access memory; f) again assigning data from the database to a cluster and determining an updated mean from the summarized data and the additional portion of data records; and g) evaluating a criteria to determine if further data should be accessed from the database to continue clustering of data from the database.