This demo shows how usage information buried in query logs can play a central role in data integration and data exchange. More specifically, our system U-Map uses query logs to generate correspondences between the attributes of two different schemas and the complex mapping rules to transform and restructure data records from one of these schemas to another. We introduce several novel features showing the benefit of incorporating query log analysis into these key components of data integration and data exchange systems. Categories and Subject Descriptors H.2.5 [Database Management]: Heterogeneous Databases General Terms Algorithms, Design Keywords Schema mapping, schema matching, query logs