Illustrate the cardinality of relationship, Database Management System

Cardinality of Relationship

One-to-One

Only one entity of the first set is linked to only one entity of the second set. E.g. A teacher teaches a student. Only one teacher is teaching only one learner.

One-to-Many

Only one entity of the first set is related to many entities of the second set. E.g. A teacher teaches learners.

Many-to-One

Multiple entities of the first set are related to many entities of the second set. E.g. Teachers teach a learner.

Many-to-Many

Multiple entities of the first set are related to multiple entities of the second set. E.g. Teachers teach learners

 

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