Chen 的 ERD 图中的属性是强制性的吗？
使用 Chen 表示法时是否必须在 ERD 图中添加属性符号？
我这么问是因为在我当前的 ERD 中已经有太多的表格和关系，需要 A3 纸张大小才能将其打印出来。添加所有属性符号会使它变得更大并且更难以阅读。因此，我想知道这是否是一项义务，或者我是否可以将它们排除在外。如果这是强制性的，我如何保持我的图表的可读性？
Is it mandatory to add the attribute symbols in an ERD diagram when using Chen's notation?
I'm asking because in my current ERD there are already so many tables and relations that an A3 paper size is needed to print it out. Adding all the attribute symbols would make it even larger and less readable. I therefore wonder if it is an obligation or if I could leave them out. And if it is mandatory, how could I maintain my diagram readable?
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（1）
在 Chen 的表示法中，并不强制要求显示属性。
在他的开创性文章中（例如此处），Chen 使用了几个仅包含实体的图表，并且他们的关系。这形成了他所说的“上层概念域”，即大局。属性的详细信息可以记录在其他地方，例如“缩放”一个或几个实体的附加图表中，或者描述每个实体内容的表格数据字典中。
除了实体和关系之外，您还可以通过显示最相关的属性来丰富此方法：所有关键属性以及一些允许读者想象实体所代表的信息类型的附加属性。这些属性属于“较低的概念模型”（陈的术语）。
如果您想要拥有所有属性，并且单独的字典不适合您，您可以将模型分解为几个较小的模型，每个模型都具有其实体和关系的所有属性。一些实体会出现在多个图表中，以允许在它们之间建立链接。然后，属性详细信息将仅在一张图表中详细说明，并隐藏在其他图表中。
It is not mandatory in Chen's notation to show the attributes.
In his seminal articles (for example here), Chen uses several diagrams with only entities and their relationships. This forms what he calls the "upper conceptual domain", i.e. the big picture. The details of the attributes could be documented elsewhere, for example in additional diagrams that "zoom" one or a few entities, or in a tabular data dictionary that describes the content of each entity.
You may also enrich this approach by showing in addition to the entities and relationships, the most relevant attributes: all the key attributes, and a few additional attributes that allow the reader to imagine the kind of information that the entity represents. The attributes belong to the "lower conceptual model" (Chen's terminology).
If you would want to shall all the attributes, and if the separate dictionary is not desirable for you, you could break the model down into several smaller models each having all the attributes for their entities and relationships. Some entities would appear in several diagrams to allow to make the link between them. The attribute details would then be detailed in only one of the diagrams and hidden in the others.