Mongodb to MySQL - 正确的关系设计答案

【问题标题】：Mongo to MySQL - Correct Relationship DesignMongodb to MySQL - 正确的关系设计
【发布时间】：2021-09-23 12:40:47
【问题描述】：

我有一个看起来像这样的 MongoDB：

Batteries
[
  { _id, voltage, capacity, energy, width, length, height, weight },
  {..}
]

Machines
[
  { _id, manufacturer, category, model, voltage, capacity, energy, height, length, width, weight},
  {..}
]

Mongo 需要转换为关系数据库。现在我为此想到的 SQL 是两种设计之一：（抱歉我如何显示我的关系，嵌入这个 html 似乎是最简单的，同时保持准确性）

图片：Same image as code snipped below

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我是使用 SQL 数据库的新手，我知道我可能在这里做错了。我倾向于底部设计（我们称之为 Design2）并将我的模型类在 .Net C# 中编写为：

public class Manufacturer
{
    public int ID { get; set; }
    public string Name { get; set; }
    public string ImgURL { get; set; }

    public List<Categories> Categories { get; set; }
}

public class Categories
{
    public int ID { get; set; }
    public string Name { get; set; }
    public int ManufacturerID { get; set; }

    public List<Manufacturer> Manufacturer { get; set; }
    public Models Model { get; set; }
}

public class Models
{
    public int ID { get; set; }
    public string Name { get; set; }
    public int CategoryID { get; set; }
    public int BatteryID { get; set; }

    public List<Categories> Categories { get; set; }
    public List<Batteries> Batteries { get; set; }
}

public class Batteries
{
    public int ID { get; set; }
    public float Voltage { get; set; }
    public float Capacity { get; set; }
    public float Energy { get; set; }
    public float Width { get; set; }
    public float Length { get; set; }
    public float Height { get; set; }
    public float Weight { get; set; }
    public bool Solar { get; set; }

    public Models Model { get; set; }
}

我是否了解如何成功设计关系，数据库是 3NF 吗？
先感谢您！我在执行此操作时使用的资源是：

【问题讨论】：

我会使用 Mysqlsh 中的 JSON 导入实用程序来加载 bson 数据，然后使用生成的列来提取所需的 JSON key.values

标签： c# mysql sql .net mongodb

【解决方案1】：

以防万一有人偶然发现这个问题并想知道发生了什么，我想通了，并找到了一种像魅力一样起作用的方法。

事实证明，我在初始模型文件中混淆了一些 1-1 和 1-many 关系。

public class Manufacturers
{
    [Key]
    public int ManufacturerID { get; set; }
    public string Name { get; set; }
    public string ImgURL { get; set; }

    public List<ManufacturerCategory> ManufacturerCategories { get; set; } = new List<ManufacturerCategory>(); //1-x
}

public class Categories
{
    [Key]
    public int CategoryID { get; set; }
    public string Name { get; set; }

    public List<ManufacturerCategory> ManufacturerCategories { get; set; } = new List<ManufacturerCategory>(); //1-x
}

public class ManufacturerCategory
{
    [Key]
    public int ManufacturerCategoryID { get; set; }
    public int ManufacturerID { get; set; }
    public int CategoryID { get; set; }

    public Manufacturers Manufacturer { get; set; } //1-1
    public Categories Category { get; set; } //1-1
}

public class Modelz
{
    [Key]
    public int ModelID { get; set; }
    public string Name { get; set; }
    public int ManufacturerCategoryID { get; set; }
    public string BatteryID { get; set; }

    public Batteries Battery { get; set; }  //1-1
    public ManufacturerCategory ManufacturerCategory { get; set; }  //1-1
}

public class Batteries
{
    [Key]
    public string BatteryID { get; set; }
    public int? Voltage { get; set; }
    public float? Energy { get; set; }
    public int? Capacity { get; set; }        
    public float? Width { get; set; }
    public float? Length { get; set; }
    public float? Height { get; set; }
    public float? Weight { get; set; }
    public bool? Solar { get; set; }
    public string? ImgURL { get; set; }
    public string? SpecsURL { get; set; }
}

【讨论】：