For example, there are now emerging theories of meta-modeling and of model transformations, which impose certain demands on how a modeling language should be defined.
例如，目前将要出现的外部模型和模型转换的理论，它强制性要求一个模型语言如何来定义。
UML is a powerful language for object-oriented modeling, but it has some explicit drawbacks. For example, it lacks a model check mechanism so it is difficult to keep the consistence of Meta model.
统一建模语言uml存在着面向对象建模的不足，例如，用多个模型表示系统，模型的一致性难以保证。
UML is a powerful language for object-oriented modeling, but it has some explicit drawbacks. For example, it lacks a model check mechanism so it is difficult to keep the consistence of Meta model.
统一建模语言uml存在着面向对象建模的不足，例如，用多个模型表示系统，模型的一致性难以保证。
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