EF 4.1 - 模型關係

Question

我試圖創建一個使用EF 4.1 RC版快速ASP.NET MVC 3應用程序。我有兩個型號：

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; } 
} 

我在嘗試插入一個新的種族，當出現以下錯誤：

無法確定之間的關聯的主要結束 類型 'rcommander.Models.Race' 和 'rcommander.Models.Address'。此關聯的 主要端必須 使用任一 的關係流利API或數據 註解明確配置。

難道不應該承認RaceId作爲競賽表的主鍵和AddressId爲FK自動將地址表？我錯過了什麼嗎？

謝謝！

Answer 1

這裏的問題似乎是EntityFramework無法識別前面的鍵，因爲您在兩個對象中都持有交叉引用。不是確定要達到什麼樣的，我建議是這樣的：

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; } 
} 

跳過參考第二實體的比賽。

Answer 2

它可以識別ID作爲按約定的主鍵。所以，你需要做什麼：

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; } 
} 

的[Key]屬性表明，它應該是PrimaryKey的

如果你不希望這樣，你需要將自己的主鍵簡單地public int Id {get; set; }

Answer 3

這裏的問題是1：地址和種族之間的關係1！你可能想將其對應爲1：N，所以你需要修改地址：

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，那麼你不能在比賽中，但在AddressId地址使用AddressId須爲外鍵因爲實體框架可以實現1：1只是「共享」主鍵。

Answer 4

有一個好的職位：協會在EF的Code First CTP5：第2部分 - 共享主鍵關聯

http://weblogs.asp.net/manavi/archive/2010/12/19/entity-association-mapping-with-code-first-one-to-one-shared-primary-key-associations.aspx

Answer 5

對於一比一的關係，你需要添加「[必需]」屬性在第二類。請看下圖：

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; } 

} 

Answer 6

我認爲這將是也解決了這樣的...我認爲不需要地址要與種族有關，但是比賽必須始終與地址相關聯。 我曾與患者和事件的發生同樣的問題，我與InverseProperty這實際上是與外鍵一樣解決它，但其他方向

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; } 

}