Here are some posts I found doing a search of this site. This is a common question; an others have answered this (I have a few posts here on this, also) far better than me.

• What is the difference between composition and aggregation?


• UML Aggregation & Composition


• Association,Generalization


• Needed some real time examples. This one gives a good link to some examples.


• Has I got it Right?

Hope this helps. If you do a search on your topic "Association, Aggrigation and Composition", you will find many more posts on this topic... and in the FAQs.

Stephen McConnell