blocks|key|1688478|text|来自DifferenceBetween.com|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1688479|1688480|+ER图表示数据模型的抽象表示，而类图表示所提议系统的静态结构和行为。ER图的主要构建块是实体、关系和属性，而类图的主要构建块是类、关系和属性。类图更有可能映射到现实世界的对象，而ER图最常映射到数据库中的表。通常，对于人类来说，ER图中的关系比类图中的关系更难理解。|blockquote|1688481|1688482|entityMap|0|LINK|mutability|MUTABLE|url|http://www.differencebetween.com/difference-between-er-diagram-and-vs-class-diagram/^0|2|L|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|-4|5|6|7|U|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|V|8|@]|9|@]|C|$]]|$1|H|3|-4|5|6|7|W|8|@]|9|@]|C|$]]|$1|I|3|-4|5|6|7|X|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

From <a href="http://www.differencebetween.com/difference-between-er-diagram-and-vs-class-diagram/" rel="noreferrer">DifferenceBetween.com</a>:

<blockquote>
 ER diagrams represent the abstract representation of the data model,
 while class diagrams represent the static structure and behavior of
 the proposed system. Main building blocks of ER diagrams are entities,
 relationships and attributes but the main building blocks of class
 diagrams are classes, relationships and attributes. Class diagram are
 more likely to map in to real-world objects, while ER diagrams most
 often map in to the tables in the database. Usually, relationships
 found in ER diagrams are more difficult to understand for humans than
 relationships in class diagrams.
</blockquote>

blocks|key|4252900|text|ER图：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4252901|4252902|数据库中包含的内容，如表、关系、主键、外键，什么是弱实体，|unordered-list-item|4252903|4252904|类图：|4252905|4252906|类中包含的内容，如属性、属性类型、方法、方法的返回类型、方法的参数、类的关系(继承、聚合等)。另外还有一个关于接口的抽象类。|4252907|4252908|ORM(对象关系映射)：|4252909|4252910|在任何language.|4252911|where中都有对象关系管理工具，您只需创建一个ER图，我们只需基于一个类创建任何类，它将自动创建一个数据库。|4252912|4252913|，因此我们不需要创建类图。|4252914|entityMap^0|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|10|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|11|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|13|8|@]|9|@]|A|$]]|$1|J|3|K|5|E|7|14|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|15|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|16|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|17|8|@]|9|@]|A|$]]|$1|P|3|Q|5|E|7|18|8|@]|9|@]|A|$]]|$1|R|3|S|5|E|7|19|8|@]|9|@]|A|$]]|$1|T|3|-4|5|E|7|1A|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1B|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|1C|8|@]|9|@]|A|$]]]|X|$]]

ER diagram:- 

<ul>
<li>what is contained in the database like the table, relationship, primary key, foreign key, what is a weak entity, </li>
</ul>

Class diagram:- 

<ul>
<li>what is contained in class like attributes, types of attributes, method, the return type of methods, method's parameter, a relationship of a class(inheritance, aggregation etc.). plus there are also about an interface, abstract class.</li>
</ul>

ORM(object relation mapping):- 

<ul>
<li>there are ORM tools available in any language.</li>
<li>where you have to create only an ER diagram from that we have to create only class any based on a class it will automatically create a database.</li>
<li>so we don't need to create a class diagram.</li>
</ul>

blocks|key|5670521|text|当您想到类图时，您想到的是行为的组织或简单的函数。例如，使用州税收信息计算成本函数。然后，您可能有不同的类来表示不同的计算功能(请参阅GoF设计模式中的策略模式)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|5670522|当您考虑ER图时，您正在考虑将存储的数据的存在和关系的规则。一个用户帐户必须有一个用户名，一个银行帐户只能有一个主用户帐户。|5670523|总而言之，使用类图可以考虑行为/功能的组织，而使用ER图可以考虑数据资产的组织。在构建整个应用程序时，这两者肯定是相关的，但在构建的应用程序设计中有两种不同的视角。|5670524|希望这个解释能有所帮助！|5670525|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|L|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|M|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

When you think of Class Diagrams, you are thinking about the organization of behaviors or simply functions. In example, calculate costs function using state tax information. Then you may have different classes representing different calculation functions (See strategy pattern from GoF design patterns). 

When you think about an ER diagram, you are thinking about the rules around the existence and relationship of data that will be stored. A user account must have a username and a bank account can have only one primary user account. 

To sum up, with class diagrams you think about the organization of behaviors/functions, while with ER diagrams you think about the organization of data assets. The two definitely relate when building an entire application, but have two different perspectives in the design of the application being built.

Hope that explanation helps!

blocks|key|4252967|text|有很多方法可以区分ERD和类图。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4252968|例如，ERD，也称为实体关系图，只描述系统特性。另一方面，类图显示了系统中最重要的部分，系统和行为特性。|4252969|在统一建模语言UML中，特性在“类矩形框”中显示为未加密的文本。然而，在实体关系图中，特征是“链接到实体类型的椭圆”。|4252970|ER图具有比类图更复杂的关系，并且更难被人类破译。ER图与类图不同，因为它“映射到数据库中的表”，而“类图”映射到实际对象。|4252971|另一个区别是类图有一些在实体关系图中没有隐含和建模的关系。|4252972|实体关系图的主要部分由实体、关系和属性组成，而类、关系和属性是类图的部分。|4252973|希望这对任何人都有帮助！|4252974|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|S|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|T|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|U|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|V|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|O|$]]

There are many ways to tell the difference between ERD and Class diagram.

For instance, ERD, otherwise known as Entity Relationship Diagram, only portrays systemic features.
On the other hand, Class Diagram displays the most vital sections of a system, the systemic and behavioural features.

In Unified Modelling Language, UML, features are shown as unencrypted text in ‘the class rectangle box’.
However, in an Entity Relationship Diagram, the features are ‘oval linked to the entity type’.

ER Diagram has relationships which are more complex than Class diagram and are more complicated to be deciphered by humans.
ER Diagram contrasts to Class diagram since it ‘maps into tables in database’ whereas Class diagram maps into actual objects.

Another distinction is that Class diagram has some relationships which are not implied and modelled in Entity Relationship Diagram. 

The main segments of Entity Relationship Diagrams consist of entities, relationships and attributes whilst classes, relationships and attributes are the segments of Class Diagrams.

Hope this helps anyone!

I have been given a description and need to draw ER diagram and Class diagram for the description. 

Now I am having issue with understanding the differences between these 2 diagrams. 
When I draw the diagrams entities of ER diagram becomes classes. I am not sure whether I am in right track. 

Please explain me what is the difference and similarities of these two?

Difference between ER diagram and Class diagram

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我已经得到了一个描述，并需要绘制ER图和类图的描述。现在，我在理解这两个图表之间的差异时遇到了问题。当我绘制这些图时，ER图的实体就变成了类。我不确定我是否在正确的轨道上。请给我解释一下这两者有什么不同和相似之处？

问ER图与类图的区别
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