A database in which, in addition to the data, the interrelationships between data are also recorded. By using relations, this can be requested and selected in various ways in different combinations. Data in a relational database is normalized and linked to keys and foreign keys. Relational database management system (RDBMS). A software system that takes care of the management (saving, reading, changing and deleting) of a relational database. Access to the relational database is provided through the user interface.