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EF 4.1 - 模型关系

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我正在尝试使用RC版本的RS 4.1创建一个快速的ASP.NET MVC 3应用程序 . 我有两个型号：

public class Race
{
    public int RaceId { get; set; }
    public string RaceName { get; set; }
    public string RaceDescription { get; set; }
    public DateTime? RaceDate { get; set; }
    public decimal? Budget { get; set; }
    public Guid? UserId { get; set; }
    public int? AddressId { get; set; }

    public virtual Address Address { get; set; }
}

和

public class Address
{
    public int AddressId { get; set; }
    public string Street { get; set; }
    public string StreetCont { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string ZipCode { get; set; }

    public virtual Race Race { get; set; }
}

尝试插入新Race时出现以下错误：

无法确定类型'rcommander.Models.Race'和'rcommander.Models.Address'之间关联的主要结束 . 必须使用关系流畅API或数据注释显式配置此关联的主要结尾 .

它不应该自动将RaceId识别为Races表的主键和AddressId作为地址表的FK吗？我错过了什么吗？

谢谢！

asp.net-mvc-3 entity-framework-4 entity-relationship ef-code-first entity-framework-4.1

6 回答

  • 0

    这里的问题似乎是EntityFramework无法识别foreing键的位置，因为您在两个对象中都持有交叉引用 . 不确定你想要实现什么，我可能会建议这样的事情：

    public class Race
{
  public int RaceId { get; set; }
  public string RaceName { get; set; }
  public string RaceDescription { get; set; }
  public DateTime? RaceDate { get; set; }
  public decimal? Budget { get; set; }
  public Guid? UserId { get; set; }

  public int? AddressId { get; set; }
  public virtual Address Address { get; set; }
}

public class Address
{
  public int AddressId { get; set; }
  public string Street { get; set; }
  public string StreetCont { get; set; }
  public string City { get; set; }
  public string State { get; set; }
  public string ZipCode { get; set; }
}

    在第二个实体中跳过对Race的引用 .

    回复于
  • 8

    这里的问题是地址和种族之间的1：1关系！您可能希望将其映射为1：N，因此您需要将地址修改为：

    public class Address
{
  public int AddressId { get; set; }
  public string Street { get; set; }
  public string StreetCont { get; set; }
  public string City { get; set; }
  public string State { get; set; }
  public string ZipCode { get; set; }

  public virtual ICollection<Race> Races { ... }
}

    如果你想使用1：1然后你不能在Race中使用AddressId但Address中的AddressId必须是Race的外键，因为实体框架只能以1：1的方式“共享”主键 .

    回复于
  • 21

    对于一对一关系，您需要在第二个类中添加“[required]”属性 . 见下文：

    public class Race
{
  public int RaceId { get; set; }
  public string RaceName { get; set; }
  public string RaceDescription { get; set; }
  public DateTime? RaceDate { get; set; }
  public decimal? Budget { get; set; }
  public Guid? UserId { get; set; }

  public int? AddressId { get; set; }
  public virtual Address Address { get; set; }
 }

public class Address
{
 public int AddressId { get; set; }
 public string Street { get; set; }
 public string StreetCont { get; set; }
 public string City { get; set; }
 public string State { get; set; }
 public string ZipCode { get; set; }

 [required]
 public Race Race { get; set; }

}
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  • 4
    回复于
  • 18

    它按惯例将Id视为主键 . 那么你需要做什么：

    public class Race
{
    [Key]
    public int RaceId { get; set; }
    public string RaceName { get; set; }
    public string RaceDescription { get; set; }
    public DateTime? RaceDate { get; set; }
    public decimal? Budget { get; set; }
    public Guid? UserId { get; set; }
    public int? AddressId { get; set; }

    public virtual Address Address { get; set; }
}
and

public class Address
{
    [Key]
    public int AddressId { get; set; }
    public string Street { get; set; }
    public string StreetCont { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string ZipCode { get; set; }

    [ForeignKey("RaceId")] // Maybe telling it what the ForeignKey is will help?
    public virtual Race Race { get; set; }
}

    [Key] 属性表示它应该是PrimaryKey

    如果您不想这样，则需要将主键重命名为 public int Id {get; set; }

    回复于
  • 5

    我认为它也会像这样解决......我认为地址不需要与种族相关联，但种族必须始终与地址相关联 . 我和患者和事故有同样的问题，我用InverseProperty解决了这个问题，实际上与外键相同，但另一个方向

    public class Race
{
  public int RaceId { get; set; }
  public string RaceName { get; set; }
  public string RaceDescription { get; set; }
  public DateTime? RaceDate { get; set; }
  public decimal? Budget { get; set; }
  public Guid? UserId { get; set; }

  public int AddressId { get; set; }

  [ForeignKey("AddressId")]
  public virtual Address Address { get; set; }
 }

public class Address
{
 public int AddressId { get; set; }
 public string Street { get; set; }
 public string StreetCont { get; set; }
 public string City { get; set; }
 public string State { get; set; }
 public string ZipCode { get; set; }

 public int? RaceId { get; set; }
 [InverseProperty("RaceId")]
 public Race Race { get; set; }

}
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