ERD中的实体与类图中的类有任何相关的概念？ [英] Entities in ERD have any related concept with classes in Class Diagrams?

问题描述

i更熟悉ERD

仅仅是为了数据库设计？

是ERD中与类中的类相关的实体图表？

ERD中的实体意味着类图中的内容？



这两个在设计时彼此无关？



请解释我

和谢谢

Hi,
i am more familiar with ERD
is erd merely for Database design?
are entities in ERD related to Classes in class diagrams?
entities in ERD mean what in Class diagram?

are these two not related to each other when designing?

please explain me
and thanks

推荐答案

您好。一般来说，设计一个数据库你需要三个步骤：



1 - 创建像ERD这样的概念数据模型：

概念模式是对
$的永久描述b $ b数据库要求。



2 - 创建逻辑数据模型（关系，普通形式）：

构建逻辑的第一步模型是坐下来从需求中创建

模型。一旦确定了各种信息之间的关系和依赖关系，就可以将数据排列成逻辑结构。然后可以将ch映射到数据库管理系统支持的存储对象。在关系数据库的情况下，存储对象是以行和列存储数据的表。



3 - 创建物理模型：

A物理模型由RDBMS的表和其他物理对象组成。



现在我们考虑类图：

类图描述系统中的对象类型以及它们之间存在的各种静态关系。类图还显示了类的属性和操作以及适用于对象连接方式的约束。



用于确定ERD中的实体您必须首先搜索名词为了确定类图中的类，你必须采取类似行动。

i在ERD中认为实体是类图中的相同类。

i希望我的想法可以帮助你。

祝你好运

Hi.Generally for designing a DataBase you need three Steps:

1-Create Conceptual Data Model like ERD:
Conceptual schema is a permanent description of the
database requirements.

2-Create Logical Data Model(Relational,Normal Form):
The first step in building the logical model is to sit down and create the
model from the requirements.Once the relationships and dependencies amongst the various pieces of information have been determined, it is possible to arrange the data into a logical structure which can then be mapped into the storage objects supported by the database management system. In the case of relational databases the storage objects are tables which store data in rows and columns.

3-Create Physical Model:
A physical model is made up of the tables and other physical objects of your RDBMS.

Now we consider Class Diagram:
A class diagram describes the types of objects in the system and the various kinds of static relationships that exist among them. Class diagrams also show the properties and operations of a class and the constraints that apply to the way objects are connected.

for detemining Entities in ERD you must first search the Nouns.for determining classes in Class Diagram you must act similarly.
i think entity in ERD are the same Classes in class diagram.
i hope my idea help you.
Good luck

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