Composition: This is where once you destroy an object (School), another object (Classrooms) which is bound to it would get destroyed too. Both of them can't exist independently.
Aggregation:
This is sorta the exact opposite of the above (Composition
) association where once you kill an object (Company
), the other object (Employees
) which is bound to it can exist on its own.
Association.
Composition and Aggregation are the two forms of association.