EF代码优先：重复的外键（一个来自名称约定，一个来自导航属性）

本文介绍了EF代码优先：重复的外键（一个来自名称约定，一个来自导航属性）的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正尝试使用EF Code First创建一个SQL数据库。

I'm trying to create an SQL database by using EF Code First.

假设我有以下代码：

public class Account { public int Id; public ICollection<User> Users; } public class User { public int Id; public int AccountId; } public class AccountContext : DbContext { public DbSet<Account> Accounts; public DbSet<User> Users; }

（请注意，缺少任何Fluent API命令或数据注释；我想

(Note the lack of any Fluent API commands or Data Annotations; I want to do this by convention.)

创建数据库后，我在Users表中获得以下字段：

When the database is created, I get the following fields in the Users table:

Id AccountId Account_Id

为什么EF不能理解 AccountId是指Account的 Id主键这一事实？我希望避免在可能的情况下使用Fluent API / DA手动进行映射，并且希望避免在用户上拥有帐户导航属性。

Why isn't EF picking up on the fact that "AccountId" refers to the "Id" primary key (by convention) of Account? I want to avoid mapping this manually with Fluent API/DA if possible, and I want to avoid having the Account navigation property on User.

推荐答案

通过数据注释（非常快速）或流利的映射，我只有两种方法可以知道如何执行您要执行的操作。您不能只说 public int AccountId; 并期望一切正常。

There are only two ways i know how to perform what you are looking to do, either by Data Annotation (Very quick) or Fluent Mapping. You can't just say public int AccountId; and expect everything to work.

Fluent API映射双向

public class Account { public int Id { get; set; } public ICollection<User> Users { get; set; } } public class User { public int Id { get; set; } public Account Account { get; set; } } public class AccountContext : DbContext { public AccountContext() : base("DefaultConnection") { } public DbSet<Account> Accounts { get; set; } public DbSet<User> Users { get; set; } protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity<User>().HasRequired(u => u.Account) .WithMany(a => a.Users) .HasForeignKey(u => u.AccountId); } }

双向数据注释

public class Account { [Key] public int Id { get; set; } public ICollection<User> Users { get; set; } } public class User { [Key] public int Id { get; set; } [ForeignKey("Account"), DatabaseGenerated(DatabaseGeneratedOption.None)] public int AccountId { get; set; } public Account Account { get; set; } } // and of course you need your context class, but with less code public class AccountContext : DbContext { public AccountContext() : base("DefaultConnection") { } public DbSet<Account> Accounts { get; set; } public DbSet<User> Users { get; set; } }

没有双向数据注释或Fluent API映射

public class Account { public int Id { get; set; } //as Id in Accounts Table public ICollection<User> Users { get; set; } } public class User { public int Id { get; set; } //as Id in Users Table public Account Account { get; set; } // as Account_Id in Users Table } // and of course you need your context class, but with less code public class AccountContext : DbContext { public AccountContext() : base("DefaultConnection") { } public DbSet<Account> Accounts { get; set; } public DbSet<User> Users { get; set; } }

我希望这可以帮助您或其他有疑问的人

I hope this helps you or anyone else in doubt

编辑

如果要避免使用双向导航，然后像这样更改个用户

If you want to avoid Bi-Directional navigation then make changes to Users like this

public class User { public int Id { get; set; } //delete below from User class to avoid Bi-directional navigation //public Account Account { get; set; } }

注意：未经测试，但逻辑是声音

Note: Not tested but the logic is sound