in Frankfurt am Main von

Data exchange deals with translating data structured in some format into data structured in some other format, according to a specification of the relationship between the source data and the target data. Such data translation tasks are very common in practice. They arise as one of the many tasks in data inte-gration, for example, in data restructuring, in ETL (Extract-Transform-Load) processes used for updating data warehouses, or in data exchange between dif-ferent, possibly independently created, applications. While systems for data exchange have been implemented over the past decades, research on the theo-retical foundations of data exchange started only recently with the influential article by Fagin, Kolaitis, Miller and Popa. This thesis deals with relational data exchange, where the source data and the target data are relational. The basic setting in relational data exchange is the following. We are given a schema mapping M that consists of a source schema (the format of the source data) and a target schema (the format of the target data), and is defined b