Logical Data Modeling - Relationship Degree (Arity)

The degree of a relationship is the number of entities that participate in the relationship.

A binary relationship has a degree = 2, because two different entities participated in the relationship

Relationships may also exist between different instances (row) of the same entity. This is called a recursive relationship

A relationship may be:

• binary (concerns only two elements)
• or multinary (concerns more than two elements) (ie a+b=c)