Model-meta-model

During my two-month long vacation, I spent some time reading 《UMLBaodian andXpdlStandardization: the concept of the metadatabase model is mentioned in the two documents. Although I have heard of the metadatabase model more than once, I realized its importance this time.

The meta-model refers to the model that describes the model. InUMLIn the figure, we use a class diagram to describe the system structure. At this time, the class diagram we draw is the model of our system, and the class diagram "--UMLOne of the seven chart concepts is our meta-model. We use it to describe our system structure. The structure described is our model-the class chart we have drawn. The process from model to meta-model is actually an abstract process. The improvement of the abstraction level makes it easier for us to grasp the development of the project and understand the structure of the entire project. It is as if all science needs certain philosophical thoughts to know. Compared with specific science, its meta level is philosophy.

Taking a class chart as an example, the result of using a class chart is the system model (the relationship between the model and the meta model may still exist in the system, which will not be discussed here ), various definitions in a class chart, such as classes, interfaces, and references, are their meta models. ForUMLAbstract to this level is enough, andUMLDesigners, classes, interfaces, references, and other elements are just their models, and their meta models are also built on them.

There is no specific boundary between the model and the meta-model, just like . Net The base classes of all classes are Object Similarly, the meta-models of all models are philosophy in the final analysis.