Relationship in DBMS

Relationship

The association among entities is called a relationship.
example, the relationship between an employee and a department is works_at.
example, relationship enrolls is used in student and course.
 

Relationship Set

A set of relationships of a similar type is called a relationship set. These attributes are also called descriptive attributes.
 

Degree of Relationship

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

Single or recursive = degree 1

The entity is related to itself it is known as Recursive Relationship.

Binary = degree 2

• A binary Relationship means the relation between two Entities.
• 
  This is further divided into three types.
• One to One Relationship
• One to many Relationship
• Many to many Relationship

 Ternary = degree 3

n-ary = degree n
A Ternary relationship involves three entities.