无法确定主要终端 - 实体框架代码第一关系

Question

请检查下面可能的解决方案部分

我有一个外键关系的问题 - 这是我的表:

public class Lead
{
    [Key]
    public int LeadId { get; set; }
    public int? CustomerId { get; set; }

    [ForeignKey("CustomerId")]
    public virtual Customer Customer { get; set; }
 }

public class Customer
{
    [Key]
    [Column("customer_id")]
    public int CustomerId { get; set; }

    [ForeignKey("CustomerId")]
    public virtual Lead Lead { get; set; }

}

我遇到了一个问题,我收到此错误:

Unable to determine the principal end of an association between the types 'Sales.Customers.Customer' and 'Sales.Leads.Lead'. The principal end of this association must be explicitly configured using either the relationship fluent API or data annotations.

我已经尝试将关系添加到模型构建器,但它似乎无法正常工作.当我收到错误信息消失它实际上使用Lead.LeadId -> Customer.CustomerId作为关系而不是Lead.CustomerId -> Customer.CustomerId关系.

我在Stackoverflow上检查了类似的问题,但它们似乎与我的数据库结构不匹配,当我尝试实现他们的建议时,关系仍然无法正常工作.

它真的很奇怪 - 非常感谢这方面的帮助!

UPDATE

所以在我试图让这种关系发挥作用时,我已经按照以下方式切换了键:

public class Lead
{
    [Key]
    public int LeadId { get; set; }

    [ForeignKey("LeadId")]
    public virtual Customer Customer { get; set; }
}

public class Customer
{
    [Key]
    [Column("customer_id")]
    public int CustomerId { get; set; }
    public int? LeadId { get; set; }

    [ForeignKey("LeadId")]
    public virtual Lead Lead { get; set; }
}

然而,同样的错误,仍然没有运气 - 我真的不知道为什么这种关系不起作用.对我而言,这看起来非常简单.

更新2

好的 - 经过一段时间的浪费,我尝试了一种略有不同的方法:

这是我的新课......

    public class Lead
    {
        [Key, ForeignKey("Customer")]
        public int LeadId { get; set; }
        public virtual Customer Customer { get; set; }
    }

    public class Customer
    {
        [Key]
        [Column("customer_id")]
        public int CustomerId { get; set; }
        public int? LeadId { get; set; }
        public virtual Lead Lead { get; set; }
     }

使用上面的代码不再有错误消息!唯一的问题是关系实体框架正在创建Customer.CustomerId和Lead.LeadId而不是Customer.LeadId和Lead.LeadId之间 - 我觉得我很接近!

可能的解决方案

好的 - 经过一些更多的研究之后,我在这里看到了这篇文章: EF Code First - 1对1可选关系

我修改了我的类:

public class Customer
{
    [Key]
    [Column("customer_id")]
    public int CustomerId { get; set; }

    public virtual Lead Lead { get; set; }
}

public class Lead
{
    [Key]
    public int LeadId { get; set; }
    public virtual Customer Customer { get; set; }
 }

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<Customer>().HasOptional<Lead>(l => l.Lead).WithOptionalDependent(c => c.Customer).Map(p => p.MapKey("LeadId"));
    base.OnModelCreating(modelBuilder);
}

一切都很棒!但是一个大问题......

我不得不从Customer Table中删除LeadId属性....所以现在我不确定如果没有要分配的LeadId属性,在创建新客户(适当时)时如何分配LeadId？

Answer 1

将其发布到 Fluent API 中，它应该可以工作。

public class Lead
{
    [Key]
    public int LeadId { get; set; }

    public virtual Customer Customer { get; set; }
 }

public class Customer
{
    [Key]
    [Column("customer_id")]
    public int CustomerId { get; set; }

    public virtual Lead Lead { get; set; }
}

builder.Entity<Lead>()
.HasOptional(l => l.Customer)
.WithOptionalPrincipal()
.Map(k => k.MapKey("LeadId"));

builder.Entity<Customer>()
.HasOptional(c => c.Lead)
.WithOptionalPrincipal()
.Map(k => k.MapKey("CustomerId"));

编辑