One embodiment of the present invention provides a system for making predictions about data records from an incoming stream of data records. This system operates by discovering predictive relationships in an online manner between fields in records in the incoming stream of data records as the incoming stream of data records is received. These predic tive relationships can used to predict values in fields based on other field values in the same record. This facilitates cleansing of data by allowing transaction values to be validated based upon predictions made from other field values in the same transaction record. It also allows missing field values to be predicted based upon the other field values. A variation of this embodiment provides for filtering transaction records based upon discovered predictive relationships and routing the transaction records to other servers in real-time. Another embodiment forms association rules between fields in records in the incoming s of records, and outputs these association rules for viewing by a human decision-maker. In another embodiment, the present invention comprises a server with an online predictive memory that can be incorporated into a heterogeneous network as a server. This embodiment is scalable and can be incorporated into an existing network with minimal integration effort. Note that the underlying model for this system continuously adapts to changes in the incoming stream of records over time without the need for any human intervention.