Matching new customer records to existing customer records in a large business database using hash key

In this invention there is a method and system for matching new customer records to existing customer records in a database. The new customer records are validated for quality and normalized into a standard form. A hash key is selected to generate a candidate set of records from the existing records in the database that likely matches the new customer records. The new customer records are then matched to each of the records in the candidate set. Once the matching has been performed, a decision is made on whether to create a new customer record, update an existing record, or save the new record in a pending file for resolution at a later time. In another embodiment, there is a methodology for learning matching rules for matching records in a database. The matching rules are then used for matching a new customer record to existing records in a database.