(PE) Groups of logically related fields which occur multiple times within a group. Periodic groups are a non-relational technique. An exAMple of a PE would be for storing the history of a person' s nAMe changes, where nAMe was kept in logically related fields such as surnAMe, first nAMe and middle nAMe - with the person having changed their nAMe more than once. [Clarification?] (1995-10-30)