Unary Relation

Unary Relation: A relationship is an association between the instances of one or more entity types in the database which represents some information. For example, a student may be related to a class by being enrolled in that class in different universities, college and school. Another example is the link between mother and children. One mother may have many children, but each children has only one mother.

A relationship between entities is given a relevant name that represent some data in the data file. or example there is a relationship between Manager and Department in the same organization or institute. A manager manages the department with in the specific organization or institute.