Question

我有以下域对象：

public class Person 
{
    public int Id {get; set;}
    public int? FatherId {get; set;}
    public int? MotherId {get; set;}
    public int? HomeChurchId {get; set;}
    public int? BirthCountryId {get; set;}

    public Parent Father {get; set;}
    public Parent Mother {get; set;}
    public Church HomeChurch {get; set;}
    public Country BirthCountry {get; set;}
}

public class Parent
{
    public int Id {get; set;}
    ...
}

public class Church
{
    public int Id {get; set;}
    ...
}

public class Country
{
    public int Id {get; set;}
    ...
}

映射Person时，所有这些属性的映射方式几乎相同：

HasOptional(p => p.Father).WithMany().HasForeignKey(p => p.FatherId);
HasOptional(p => p.BirthCountry).WithMany().HasForeignKey(p => p.BirthCountryId);    
...

问题是，使用BirthCountry，当我尝试查询Person时收到以下错误：

One or more validation errors were detected during model generation:

System.Data.Entity.Edm.EdmAssociationType: : Multiplicity conflicts with the
referential constraint in Role 'Person_BirthCountry_Target' in relationship
'Person_BirthCountry'. Because all of the properties in the Dependent Role are 
non-nullable, multiplicity of the Principal Role must be '1'.

如果我删除BirthCountry属性（和映射），一切正常。令我困惑的是，BirthCountry的设置就像Person中的其他所有可空属性一样。为什么其他属性没有给我同样的错误？

感谢您提供的任何帮助！

Answer 1

无知不是幸福......它只是令人沮丧。

我终于意识到我在BirthCountryId上有[Required]属性。这导致了问题......这完全有道理。我不能告诉EF它是可选的和同时需要的。

希望这能让其他人免于我遇到的同样的挫折。

简单映射时的EF 5.0多重性错误

1 个答案: