ER图和EER图之间的区别 [英] Difference between ER diagram and EER diagram

问题描述

ERD(实体关系图)和EERD(增强型实体关系图)之间有什么区别?

解决方案

实体关系模型

您有关系(图片来源)

和属性(图像源)

也可以是主键(图片来源)

增强的实体关系模型

您拥有与ER模型相同的版本

专业化

分区(多个专业)

概括

聚合

键的注释方式不同:

What is the difference between ERD (Entity relationship diagram) and EERD (enhanced entity relationship diagram)?

解决方案

Entity-Relationship model

You have relationships (image source)

and attributes (image source)

that can also be primary keys (image source)

Enhanced entity–relationship model

You have the same as with the ER model plus

specialisation

partitioning (which are multiple specialisations)

generalisation

aggregation

keys are annotated differently:

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