流利的API-一对多 [英] Fluent API - one to many

问题描述

我似乎无法在流畅的API中找到一对多的关系语法。

I cannot seem to find a one-to-many relationship syntax in the fluent API.

例如，我有两个如下表

用户

Id
Name

UserHistory

Id
UserId
Date

我有以下课程

public class User 
{
     public int Id { get; set; }
     public virtual ICollection<UserHistory> Histories { get; set; }
}

public class UserHistory
{
     public int Id { get; set; }
     public int UserId { get; set; }
     public DateTime Date { get; set; }
}

我尝试了以下操作，但不确定其是否正确。

I have tried the following but I am not sure if its actually correct.

modelBuilder.Entity<User>()
       .HasRequired(w => w.Histories)
       .WithMany();

modelBuilder.Entity<User>()
       .HasMany(f => f.Histories)
       .WithOptional()
       .HasForeignKey(f => f.UserId);

一对多关系的正确语法是什么？

What is the correct syntax for one-to-many relationship?

从技术上讲，我可以通过添加一个新表将其分解为多对多，但我不想引入另一个表。

Technically I could break it down to a many-to-many by adding a new table but I didn't want to introduce another table.

推荐答案

在您的模型中， User 实体有很多 历史记录 ，每个历史记录都有一个必需 用户，并且关系为具有一个名为 UserId 的外键：

In your model a User entity has many Histories with each history having a required User and the relationship has a foreign key called UserId:

modelBuilder.Entity<User>()
   .HasMany(u => u.Histories)
   .WithRequired()
   .HasForeignKey(h => h.UserId);

（该关系必须是必需的（非可选），因为外键属性 UserId 不能为空。）

(The relationship must be required (not optional) because the foreign key property UserId is not nullable.)

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