Data warehouses are the core of many companies’ data analysis processes. They contain various database schemas, which are designed and created through schema transformation and integration. These processes are complex and require technical knowledge, which makes them costly and prevents business teams to start new analyses independently. BCNF∗ is a web application that enables users to safely explore valid schema transformations and generate transformation scripts automatically. It can be used for any schema transformation, but is optimized for semi-automatic data warehouse creation through means like a dedicated star schema mode.