ef-code-first - EF Code First - Fluent API(WithRequiredDependent 和 WithRequiredPrincipal)

Question

我有以下类(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; }
}

要点:

Bride和 Groom需要属性

一对一的关系

在 User类，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();

但我不能被要求!

数据库中的所有文件都为空!。

如何将数据库中的字段设为非空？
如果可能，请使用 API Flient .

Answer 1

应该是这样的:

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.

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

重要提示:你不认为你想要的配置会产生死锁吗？我没有测试过上面的代码，但这个配置对我来说似乎是一个死锁，所以我不确定 EF 是否允许你创建它。用户必须需要一对夫妇，我猜夫妇必须需要同一个用户。