EF代码优先 - 流畅的API（WithRequiredDependent and WithRequiredPrincipal） [英] EF Code First - Fluent API (WithRequiredDependent and WithRequiredPrincipal)

问题描述

我有以下类：

  public class User 
 {
 public Guid Id {get;组; } 
 public string Name {get;组; } 
 public夫妇{get;组; 
} 
 
 public class Couple 
 {
 public Guid Id {get;组; } 
 public User Groom {get;组; } 
 public User Bride {get;组; 
} 
  

重点：

1. 新娘和 Groom 属性是必需的


2. 一对一的关系


3. 在 User 类中，它是 Couple 需要

OnModelCreating中的DbContext

  modelBuilder.Entity< User>（）。HasRequired（u => u.Couple）.WithRequiredPrincipal（）; 
 modelBuilder.Entity< Couple>（）。HasRequired（u => u.Bride）.WithRequiredDependent（）; 
 modelBuilder.Entity< Couple>（）。HasRequired（u => u.Groom）.WithRequiredDependent（）; 
  

但我不能要求！

数据库中的所有文件都为空。

如何使数据库中的字段不为空？
如果可能，使用API​​ Flient 。

解决方案

应该是这样的： p>

  modelBuilder.Entity< User>（）。HasRequired（u => u.Couple）.WithRequiredDependent（）; 
 modelBuilder.Entity< Couple>（）。HasRequired（u => u.Bride）.WithRequiredDependent（）; 
 modelBuilder.Entity< Couple>（）。HasRequired（u => u.Groom）.WithRequiredDependent（）; 
  

HowRequiredDependent如何工作：配置关系需要：在关系的另一边没有导航属性要求。正在配置的实体类型将是依赖关系，并且包含主体的外键。







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含义：让我们在这里考虑你的第一行代码。它在正在配置的实体（用户）中创建一个外键，使其依赖，并使关系的另一面（ Couple ）校长

---

重要提示：你认为你想要的配置会产生一个僵局吗？我没有测试上面的代码，但这个配置似乎是一个死锁给我，所以我不知道如果EF允许你创建它。用户必须需要一对夫妇，而夫妇必须需要同样的用户。

I have the following class:

public class User
{
    public Guid Id { get; set; }
    public string Name { get; set; }
    public Couple Couple { get; set; }
}

public class Couple
{
    public Guid Id { get; set; }
    public User Groom { get; set; }
    public User Bride { get; set; }
}

Important points:

1. Bride and Groom properties are required
2. One-to-one relationship
3. In the User class, it is Couple required

DbContext in OnModelCreating

modelBuilder.Entity<User>().HasRequired(u => u.Couple).WithRequiredPrincipal();
modelBuilder.Entity<Couple>().HasRequired(u => u.Bride).WithRequiredDependent();
modelBuilder.Entity<Couple>().HasRequired(u => u.Groom).WithRequiredDependent();

But I can not be required!

All fileds are with null in the database!.

How do I get the fields in the database as not null? If possible using the API Flient.

解决方案

It should be this :

modelBuilder.Entity<User>().HasRequired(u => u.Couple).WithRequiredDependent();
modelBuilder.Entity<Couple>().HasRequired(u => u.Bride).WithRequiredDependent();
modelBuilder.Entity<Couple>().HasRequired(u => u.Groom).WithRequiredDependent();

How WithRequiredDependent Works : Configures the relationship to be required:required without a navigation property on the other side of the relationship. The entity type being configured will be the dependent and contain a foreign key to the principal. The entity type that the relationship targets will be the principal in the relationship.

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Meaning : Let's consider your first line of code here. It creates a foreign key in the entity being configured (User) making it Dependant and making the other side of the relationship (Couple) Principal

---

Important : Don't you think the configuration you desire will generate a deadlock? I've not tested the code above, but this configuration seems to be a deadlock to me so i'm not sure if EF would allow you to create it. User must need a Couple, and Couple must need that same user i guess.

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