Has-A Relationship

In OOP, Has-A relationships are relationships where one object contains, or controls another object. It is contrasted with an Is-A relationship.

Objects having Has-A relationships are models for composition, or an object being contained inside of the parent object.

Examples of Has-A Relationships:

• A Person object has-a(n) Address Object.

• A Teacher Object has-a Student Object.

• A Car Object has-a Tire Object.

• A Document Object has-a Keyword or Tag Object.

• Generically, an Object has-a DAO or Gateway Object.

In these examples, you notice that the objects are not related in a parent-child type of relationship. They (typically) cannot respond to the same type of events or messages.

Contrast this with the Is-A relationship that are models for Inheritance.

Navigation

• Home
• Glossary Index
• Latest Edits

Current Page

• Edit
• Page History

User Functions

Login / Register