Tuesday, October 21, 2008

Lesson on Multiplicity

One concept in relationships is what is called Multiplicity. It shows the number of objects that can participate in a relationship.

To illustrate, here are some examples:

Relationship Example
One To One One class occupies one classroom
One To Many One teacher teaches many classes
Many To Many One teacher teaches many students. One student learns from many teacher. So in short, it's 2 One To Many relationships combined.