Two entities of one or two types associated by virtue of a defined relationship.
Relationship, Pairing and Grouping
Entities are the occurrences of an entity type, but what is an occurrence of a relationship? It can be thought of as an association between two entities. This is known as a pairing. For example, "Hamlet written by Shakespeare" is an occurrence of the relationship "written by."
When you want to consider an AUTHOR and all the BOOKs the author has written, use the term grouping. Given joint authorship, a grouping could consist of a book and all the authors who helped write it; conversely, there would be a grouping for each author and all the books the author had written. In effect, a grouping is a set of pairings.
Example to Help Distinguish Between Pairing and Grouping
This example has 2 entity types, 7 entities, 5 pairings and 2 groupings.
Pairing Action
An action on one or more pairings of a given relationship by an elementary process following an action on an entity.
Pairing Membership
The participation of an entity in a pairing.
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