Analysis Patterns: Reusable Object Models

5. Referring to Objects

Much of object orientation focuses on the idea of object identity. Within an OO computer system, each object has a unique ID, which is used as a guarantee that any object can be directly accessed. This notion affects our conceptual thinking, too. Few object methods use primary and secondary keys, which play a major role in traditional data modeling. We still need some way to refer to a particular object: For example, I might need to find a particular person to whom I need to send a bill, and a doctor may need to mark a patient as suffering from diabetes. Object systems provide us with powerful browsing capabilities that exploit the natural relationships between conceptual objects, but sometimes a more explicit identifier ...