Degree of a Relationship

Posted by AJ × 04:25

The number of participating entities in a relationship is known as the degree of the relationship.

If there are two entity types involved it is a binary relationship type

If there are three entity types involved it is a ternary relationship type

It is possible to have a n-array relationship (e.g. quaternary or unary).

Unary relationships are also known as a recursive relationship.

It is a relationship where the same entity participates more than once in different

roles.

In the example above we are saying that employees are managed by employees.

If we wanted more information about who manages whom, we could introduce a

second entity type called manager.

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