Interoperability refers to the functionality of information systems to exchange data and to enable sharing of information. Several large-scale databases have been set up at EU level to deal with migration, asylum and internal security. These databases contain information about people. Initiatives have been taken to identify and develop where and how these systems could communicate with each other and exchange information. Each of these systems has been created for a specific purpose. In keeping with the main data protection principles, interoperability cannot give rise to the access or use of any data via another information system or give access to more data than is needed.