Groups can be stored in, and retrieved from a DataBase object. The methods defined in generic class DataBase, or in its derived classes, that are devoted to the manipulation of Group objects, are presented here. In the DataBase, the Group objects are stored in a mapping associating their names to the Group, allowing retrieval of the Group when needed.
A distinction is made between the simple manipulation of Groups described in section I.1.2.1 and the more complicated operation where new Groups are created by association operations (section I.1.2.2). The methods related to these associative operations are often defined in the specialized versions of the Database class.