What is the degree of relationship set in DBMS?

The number of entity types which took part in the entity relationship is called the degree of relationships.

There are three different types of degree of relationships, they are as follows −

• Unary relationship

• Binary relationship

• Ternary relationship

Unary relationship

It is the relationship between the instances of a single entity type. It is also called a recursive relationship.

Example

A person is married is a one-to-one relationship between the instances of Person entity type of unary relationship.

Binary relationship

It is the relationship between the instances of two different entity types. Two entities will participate in the relationship.

For Example

Person and events are two different entity types which are related by using the relationship called “attends”.

Ternary relationship

A simultaneous relationship between the instances of three entity types with unique attributes is called a ternary relationship.

Example

Consultant, client and contract are three different entities with different attributes.

These three entities are related with a single relationship called “signs”.