1. A method for use by a database manager in extracting information from a relational database in response to a joining query, the relational database including a hub table and a plurality of dimension tables, each dimension table including a plurality of records each of which includes a plurality of fields, wherein each dimension table is related to the hub table by a key field such that each dimension table includes in each record such a key field and the hub table also includes the key field, the joining query selecting at least one field from at least one dimension table, the method comprising the steps of: a) examining the joining query and providing an aliasing list indicating at least one field from at least one dimension table indicated in the joining query and also indicating the identity of the at least one dimension table, the aliasing list thereby providing a list of to-be-aliased fields and corresponding dimension table identities; b) providing an alias table for the at least one field in the aliasing list, the alias table including each value of the field occurring in the at least one dimension table and also including an alias value for each value of the field, and using as the alias value the value of the key field relating the dimension table to the hub table, the alias table thereby providing a table of alias field values and corresponding aliased field values; and c) transforming the joining query into a reduced query in which the aliased field values are replaced by the alias values.