Association vs Aggregation vs Composition

Association

Defines relation between two objects
All entities are different from each other
For example, if Ram is friend of Shayam, Shayam is friend of Hari. All three are different individuals.

Aggregation

Aggregation is subset of association, where the relation between the objects is more compared to association.
Ripened fruits and seeds, fruit use seed for next generation
It can be thought as one entity using the other

Composition

Composition is also subset of association where bonding or relation is maximum
One entity cannot exist if the host is not available
For example, one room cannot become part of another house, room doesn’t exist if the house is demolished.
It’s also called death relationship.

Another metaphor can be, child in mother’s womb is composition, dependent child or infant is aggregation, adult child and mother is association. The dependency of the child on the mother gradually decreases as the child grows from birth to adult hood.

In UML, the

Association is defined by --------->

Aggregation is defined by ---------<>

Composition is defined by ---------<filled>

For full video visit

https://www.youtube.com/watch?v=5-_cud4pOp8&feature=youtu.be

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