UML 中的组合 [英] Composition in UML

问题描述

在考虑组合时在 UML 图中.我们应该在逻辑或实现意义上使用它.两个术语的示例:

In UML diagrams when considering composition. Should we use it in logical or implementation sense. Examples for both terms:

• 实施 - 机场将包含对国家/地区的引用.换句话说，一个国家是机场的一部分.
• 逻辑 - 一个国家可以有零个或多个机场.换言之，机场是国家的一部分.

从上图中，哪种情况显示了组合的正确用法?注意:如果这两种情况都不好，请提出其他方式来表示国家和机场之间的关系.

From diagram above, which case shows correct usage of composition? NOTE: if neither of these cases are good, please suggest other ways to show relationship between country and airport.

推荐答案

我认为这不是一个具有强烈UML 意义"的词.

I think that this is not a composition in the strong "UML sense" of that word.

来自维基百科:

组合和组件之间的关系是一种很强的has a"关系，因为组合对象获得了组件的所有权.这意味着组合负责组件部分的创建和销毁.

机场不会创建国家(在 IT 意义上，国家"对象也不负责提供/创建机场"对象).

An Airport does not create countries (and in IT sense, a "country" object is also not responsible for providing/creating "airport" objects).

从这个意义上说，您希望在这里建立关联；我认为第一个更合适(用一般"说话).但核心方面是:你的模型必须表达你领域的具体需求.换句话说:两个解决方案都是有效的；这在很大程度上取决于选择哪一个的上下文.换句话说:您选择一个可以帮助您解决问题的方法！

In that sense, you are looking towards an association here; and I think the first one fits better (talking in "general"). But the core aspect is: your model has to express the specific requirements of your domain. In other words: both solutions are valid; it very much depends on the context which one to choose. In other words: you pick the one that helps you solving your problem!

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