Time to sharpen your OO skills with this new article from Devshed which comes complete with worked out code samples and covers Object Interaction in PHP and Object Composition.

Composition is an important concept in PHP. It occurs when an object creates another object; that is, the first object completely possesses the second object. In this article (the first of two parts), Alejandro Gervasio explains composition, and shows some examples to illustrate his points.