Unary Relationship in DBMS

Unary Relationship in DBMS


In this article, we will learn about Unary Relationship in DBMS.

  • A relationship represents the association between two are more entities
  • The relationship also shows the different entity sets that are participating in a relationship, these relationships very much useful analyzing the design process of the system

We have observed unary, binary n-ary, recursive, ternary relationships in a database design schema. Here  we will discuss how unary relationship exists.

Unary Relationship in Entity Relationship Diagram in DBMS

Unary relationship

When there is only one entity set participating in a relationship then such type of relationship is called unary relationship

Example of unary relationship

For example, a person has only one passport and only one passport is given to only one person and hence unary relationship is observed

2 comments on “Unary Relationship in DBMS”

  • sid

    The example for unary relationship is wrong it seems. You have provided two entities in the example(Citizen and Passport) but in the definition itself you provided “only one entity”.i think unary relationship is same as recursive(i.e relationship between same entity). Correct me if I am wrong.

    • Vaibhav Jain

      Sid, read the example also, from there you’ll understand that unary relationship is the phenomena where the entities are attached in a single relationship like each particular person has a distinctive mobile number, no two person can have the same number, and the same number cannot be alloted to two different persons, I hope this will help you out