带有自动编号的实体框架外键插入 [英] Entity Framework Foreign Key Inserts with Auto-Id

问题描述

我有2个实体User和User_Profile（一对一关系）。我将它们链接如下：

 公共类用户
 {
 [Key] 
 [ForeignKey（ user_profile）] 
 public int user_id {get; set;} 
 
公共字符串用户名{get; set;} 
公共字符串email {get; set; } 
 
公共虚拟User_Proile user_profile {get; set;} 
} 
 
 
公共类User_Profile 
 {
 [Key ] 
 public int user_id {get; set;} 
 
 public string firstname {get; set;} 
 public string lastname {get; set;} 
} 
  

user_id是SQL Server的User和User_Profile表中的PK。

当我尝试通过EFDBContext Add / SaveChanges插入新记录时，它也被设置为身份列。

我收到以下错误： User_Profile表中的user_id不能为NULL这是一个PK列，因此非常合理。我希望EF可以在保存时从Users中获取Identity user_id并将其插入User_Profile user_id中。

有可能吗？如果可以，我将如何实现？

更新：请注意，我手动创建了数据库表和代码类，因此无法通过.edmx文件访问StoreGeneratedPattern。

解决方案

我认为有必要使用Fluent API显式配置您的一对一关系：

 公共类MyContext：DbContext 
 {
 // ... ...您的DbSet 
 
受保护的覆盖无效OnModelCreating（DbModelBuilder modelBuilder）
 {
 modelBuilder.Entity< User>（）
 .HasRequired（u => u.user_profile）
 .WithRequiredPrincipal（）; 
} 
} 
  

以及实体类：

 公共类用户
 {
 [Key] 
 public int user_id {get; set;} 
公共字符串用户名{get; set;} 
公共字符串电子邮件{get; set;} 
公共虚拟User_Profile user_profile {get; set;} 
} 
 
 public类User_Profile 
 {
 [键] 
 [DatabaseGenerated（DatabaseGeneratedOption.None）] 
 public int user_id {get; set;} 
 public string firstname {get; set ;} 
公用字符串姓氏{get; set;} 
} 
  

必须将 DatabaseGeneratedOption 从 Identity 切换为 None 的课程。我已经交换了主体和从属关系，因为 User 应该是主体。不需要 [ForeignKey（...）] ，因为EF会识别中的 user_id User_Profile 作为 User 的FK属性。

像这样的代码...

 使用（var context = new MyContext（））
 {
 var user = new User（） ; 
 var userProfile = new User_Profile（）; 
 
 user.user_profile = userProfile; 
 
 context.Users.Add（user）; 
 context.SaveChanges（）; 
} 
  

...应该可以正常工作，然后将两个相关实体保存到数据库。

I have 2 Entities User and User_Profile (one to one relationship). I have linked them as follows:

public class User
{
   [Key]   
   [ForeignKey("user_profile")]
   public int user_id {get;set;}

   public string username {get;set;}
   public string email {get;set;}

   public virtual User_Proile user_profile {get;set;}
}


public class User_Profile
{
   [Key]   
   public int user_id {get;set;}

   public string firstname {get;set;}
   public string lastname {get;set;}
}

user_id is a PK in both SQL Server's User and User_Profile tables. It is also set as an Identity column in the User table.

When I try to insert a new record via the EFDBContext Add/SaveChanges. I get the following error: "user_id cannot be NULL in the User_Profile table" This makes perfect sense as this is a PK column. I was hoping EF would be able to take the Identity user_id from Users and Insert it into User_Profile user_id when saving.

Is this possible and if so how would I implement that?

UPDATE: Please note that I manually created the DB tables and code classes so I dont have access to StoreGeneratedPattern via the .edmx file.

解决方案

I think it is necessary to configure your one-to-one relationship explicitely using Fluent API:

public class MyContext : DbContext
{
    // ... your DbSets

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User>()
            .HasRequired(u => u.user_profile)
            .WithRequiredPrincipal();
    }
}

And the entity classes:

public class User
{
    [Key]   
    public int user_id {get;set;}
    public string username {get;set;}
    public string email {get;set;}
    public virtual User_Profile user_profile {get;set;}
}

public class User_Profile
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.None)]
    public int user_id {get;set;}
    public string firstname {get;set;}
    public string lastname {get;set;}
}

It's necessary to switch off DatabaseGeneratedOption from Identity to None in one of the classes. I have swapped principal and dependent as it seems that the User should be the principal. The [ForeignKey(...)] is not necessary because EF will recognize user_id in User_Profile as a FK property to User.

A code like this...

using (var context = new MyContext())
{
    var user = new User();
    var userProfile = new User_Profile();

    user.user_profile = userProfile;

    context.Users.Add(user);
    context.SaveChanges();
}

...should work then as you expect and save both related entities to the database.

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