• association - is a relationship between two objects (e.g. owners feed pets, pets please owners)
• aggregation or composition - are subsets/special-cases of association (e.g. a tail is a part of both dogs and cats)
  • aggregation implies a relationship where the child CAN exist independently of the parent (e.g. Class (parent) and Student (child). Delete the Class and the Students still exist)
  • composition implies a relationship where the child CANNOT exist independent of the parent (e.g. House (parent) and Room (child). Rooms don’t exist separate to a House)
    • is a subset/special-case of aggregation
• generalization - uses “is-a” relationship (e.g. cat is a kind of pet)
• specialization - opposite of generalization
• realization - is a relationship between the blueprint class and the object containing its respective implementation level details