c# - 如何在 Entity Framework 中使用流利的 api 为一对零指定外键属性..一个关系

Question

我有一个表User 和另一个表Company。 用户可以注册零个或一个公司。

User (1)---> (0..1) Company

我的用户类别:

public class User {
    public string Id {get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }

    public string FullName
    {
        get { return FirstName + " " + LastName; }
    }

    //Relations
    public virtual Company Company { get; set; }

}

我的公司类(class)是:

public class Company {
    public int Id { get; set; }        
    public string CompanyName { get; set; }
    public string TaxNumber { get; set; }
    public string TaxOffice { get; set; }
    public string OfficeTel { get; set; }
    public string FaxNumber { get; set; }
    public string WebSite { get; set; }
    public string Address { get; set; }
    public string About { get; set; }

    //keys
    public int CityId { get; set; }
    public int StateId { get; set; }                
    public string UserId { get; set; }

    //relations
    public City City { get; set; }
    public State State { get; set; }        
    public User User { get; set; }
}

公司使用的fluent api是这样的:

public class CompanyConfiguration : EntityTypeConfiguration<Company>
{
    public CompanyConfiguration()
    {
        this.HasRequired(x => x.User)
            .WithOptional(x => x.Company);

        this.HasRequired(x => x.City)
            .WithMany(x => x.Companies).HasForeignKey(x => x.CityId).WillCascadeOnDelete(false);

        this.HasRequired(x => x.State)
            .WithMany(x => x.Companies).HasForeignKey(x => x.StateId).WillCascadeOnDelete(false);

        this.Property(x => x.Address).HasMaxLength(400);
        this.Property(x => x.CompanyName).HasMaxLength(100).IsRequired();
        this.Property(x => x.FaxNumber).HasMaxLength(20);
        this.Property(x => x.OfficeTel).HasMaxLength(20);
        this.Property(x => x.TaxNumber).HasMaxLength(20).IsRequired();
        this.Property(x => x.TaxOffice).HasMaxLength(50).IsRequired();
        this.Property(x => x.WebSite).HasMaxLength(200);            
    }
}

在我运行 Add-Migration 后，我期望的是 UserId 用作 Company 中 User 的外键> 表，但是 Entity Framework 迁移生成的是:

CreateTable(
            "dbo.Companies",
            c => new
                {
                    Id = c.Int(nullable: false, identity: true),
                    CompanyName = c.String(nullable: false, maxLength: 100),
                    TaxNumber = c.String(nullable: false, maxLength: 20),
                    TaxOffice = c.String(nullable: false, maxLength: 50),
                    OfficeTel = c.String(maxLength: 20),
                    FaxNumber = c.String(maxLength: 20),
                    WebSite = c.String(maxLength: 200),
                    Address = c.String(maxLength: 400),
                    About = c.String(),
                    CityId = c.Int(nullable: false),
                    StateId = c.Int(nullable: false),
                    UserId = c.String(),
                    User_Id = c.String(nullable: false, maxLength: 128),
                })
            .PrimaryKey(t => t.Id)
            .ForeignKey("dbo.Cities", t => t.CityId)
            .ForeignKey("dbo.States", t => t.StateId)
            .ForeignKey("dbo.AspNetUsers", t => t.User_Id)
            .Index(t => t.CityId)
            .Index(t => t.StateId)
            .Index(t => t.User_Id);

问题是我如何强制 Entity Framework 使用我指定的属性作为关系的外键，原因是我的代码中经常需要公司的 userId 值，我不想使用 Company.User.Id 表达式来获取它。

注意:我使用 Entity Framework 6.1.2 和 asp.net mvc 5

Answer 1

下面是我将如何定义这种关系中的外键:

public class Company {
   public int Id { get; set; }        

   [Required]
   [Key, ForeignKey("User")]
   public string UserId { get; set; }       

   public User User { get; set; }
}