Degree of Relationship

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The number of participating entity types in a relationship is called Degree of Relationship.

Binary Relationship

A relationship of degree two is called binary relationship. The Relational Database and E-R Model recognize, only, Binary Relationship for detailed information of the data flow. An instance, an I.T. Company is formed with many Departments and each Department is formed with Employees.



Ternary Relationship

A relationship of degree three is called ternary relationship. The Ternary and N-ary Relationships should be redesign into to multi level Binary Relationship. An instance, an I.T. Company is developed and maintaining many Projects with many Tasks. Each Task is assigned to one or many Employees.



Unary Relationship

A relationship of degree one is called recursive relationship. Recursive Relationship, one instance of an entity (Employee) is associated with another instance of same entity (Employee). An instance, an I.T. Company is formed with many Departments and each Department is formed with many Employees. Employees are managing by Department's Manager.

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