What is the difference between the different Atlas relationship categories e.g. AGGREGATION, ASSOCIATION, COMPOSITION.
What are the requirements and limitations of each, and what are some use cases?
Relationship category determines the style of relationship around containment and lifecycle. UML terminology is used for the values. ASSOCIATION is a relationship with no containment. COMPOSITION and AGGREGATION are containment relationships. The difference being in the lifecycles of the container and its children. In the COMPOSITION case, the children cannot exist without the container. For AGGREGATION, the life cycles of the container and children are totally independent.