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what is binary relationship? explain with example - Computer science fundamentals tutorial


Cardinality/Binary relationship

Cardinality/Binary relationship defines the numerical attributes of the relationship between two entities or entity sets.
Types of Cardinality/ Binary relationship
Cardinality/ Binary relationship are four types. now discuss all types of Binary relation ship.
One to one relationship : -
When a single instance of an entity is associated with a single instance of another entity then it is called one to one relationship.
For example : - a person has only one passport and a passport is given to one person.






One to many relationship : -
When a single instance of an entity is associated with more than one instance of another entity then it is called one to many relationship.
For example: -
One customer can placed many orders but an order can’t be placed by many customers.



Many to One relationship: -
When more than one instance of an entity is associated with single instance of another entity then it is called many to one relationship.
For example: -
Many students can study in a single college but a student in many colleges at same time.





Many to many relationship: -
When more than one instance is associated with more than instance of another entity then it is called many to many relationship.
For example: -
More than one employee assigned to many project and many project can be assigned to many employee.






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