Abstract
Integration is one of the most important aspects of a Data Warehouse. When data passes from the sources of the application-oriented operational environment to the Data Warehouse, possible inconsistencies and redundancies should be resolved, so that the warehouse is able to provide an integrated and reconciled view of data of the organization. We describe a novel approach to data integration and reconciliation, based on a conceptual representation of the Data Warehouse application domain. The main idea is to declaratively specify suitable matching, conversion, and reconciliation operations to be used in order to solve possibile conflicts among data in different sources. Such a specification is provided in terms of the conceptual model of the application, and is effectively used during the design of the software modules that load the data from the sources into the Data Warehouse.