(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)