Data Selecting for synchronization

A method for selecting a data set to be synchronized from databases of a data system, in which system metadata illustrating the relationships between data units of the data system are stored for the selection of the data set to be synchronized. The metadata comprises at least information on the relevance between the data units. When a first data set is to be synchronized, metadata associated with at least one initial data unit of the first data set is retrieved. Next, a second data set, which according to at least one metadata element comprises a data unit of maximum relevance to the initial data unit, is selected for synchronization.