因為菱形也有可能是空的 因此在 Static 的圖上有雖然有 Member Field, 但有可能是空的 Aggregation: has a
Composition: is a part of (owns a)
1UML Knowledge Li-Wei Cheng
UML related knowledge - 12 Association The most abstract way to describe relationship between classes A kind of link between two classes or more Any relationship between object of two classes
UML related knowledge - 23 Weak Association (Dependency) If class A’s methods include parameter of Class B’s reference, or returns reference of Class B, it calls A depends on B. Strong Association If class A holds class B’s reference, it calls A have strong association with B.
UML related knowledge - 34 Aggregation (Association with part/whole relation) A part of relationship between Class A (whole) and Class B (part) Also called shared association Doesn’t state in any way that Class A owns Class B nor that there’s a parent-child relationship between the two
UML related knowledge - 45 Composition (Association with strong life cycle relation) A strong life cycle dependency between the two, meaning that when Class A is deleted then Class B is also deleted as result. Also called not shared association. Use more specific composition link instead of the aggregation link or association link.