1. A method of migrating data between hierarchical databases comprising the steps of: a) providing a classifier for a first hierarchical database containing data; b) creating a mapping between said first hierarchical database and a second hierarchical database, wherein said mapping describes how said data which is contained within said first hierarchical database is to be organized within said second hierarchical database; c) merging said mapping between said first hierarchical database and said second hierarchical database with said classifier for said first hierarchical database; and d) migrating said data from said first hierarchical database to said second hierarchical database, wherein said merged mapping is used as the classifier for said second hierarchical database.