Relationship between data in Database Management System

Relationship is an association between the entities. A relationship may associate an entity with itself.

There are are four different types of relationships among the entites. They are,

1) One - to - One
2) One - to - Many
3) Many - to - One
4) Many - to - Many

One - to - One Relationship in Database Management System

A relationship between one entity to only one other entity is called One - to - One relationship.

One - to - Many Relationship in Database Management System

A relationship between one entity to more entity is called One - to - Many relationship.

Many - to - One Relationship in Database Management System

A relationship between more entities with one entity is called Many - to - One.

Many - to - Many Relationship in Database Management System

A relationship between by more entities with more entities is called Many - to - Many.