多重约束违反实体框架5 [英] Multiplicity constraint violated Entity framework 5

问题描述

您好我有3类人，用户配置（它继承人）和结果，一个人可以有一个或多个结果，当我尝试添加IA导致一个人艾得到标题提到的错误，我的班波纹管。任何帮助将是AP preciated。

Hello i have 3 classes Person, UserProfile(it inherits Person) and Results, a Person can have one or more results, when i try to add i a result to a person a i get the error mentioned in the title, my classes are bellow. Any help would be appreciated.

[Table("People")]
public class Person : IPerson
{

    [Key]
    [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string Name
    {
        get
        {
            return FirstName + " " + LastName;
        }
        set{}
    }

    public string Email { get; set; }
    public DateTime? LastModified { get; set; }
    public virtual ICollection<Result> Results { get; set; }
}

该用户配置类

[Table("UserProfile")]

public class UserProfile : Person
{
    public UserProfile()
    {
        Faculty = new Faculty();
        Projects = new Collection<Project>();
    }
    public string UserName { get; set; }
    public string CNP { get; set; }
    public virtual Faculty Faculty { get; set; }
    public virtual ICollection<Project> Projects { get; set; }
}

结果类

public abstract class Result:INamedEntity
{
    protected Result()
    {
        ResultType = new ResultType();
    }
    public int Id { get; set; }
    public string Name{get;set;}
    public virtual ResultType ResultType { get; set; }
    public DateTime? LastModified { get; set; }
}

问题的功能。

public void AddResultForUser(int userId, Result result)
{
    _ctx.Users.Single(u => u.Id == userId).Results.Add(result);
}

每当调用此函数调用我在 _ctx.SaveChanges（）

我得到的休耕误差

Multiplicity constraint violated. The role 'Person_Results_Source' of the relationship 'Repository.Person_Results' has multiplicity 1 or 0..1.

感谢您。

推荐答案

您试图在同一结果添加到多个用户？

Are you trying to add the same Result to several users?

在这种情况下，这将失败，因为实体框架将实现结果的人类的集合作为一个外国从键结果到人。映射将是一样的，如果您有一个人导航属性添加到结果类。

In that case this will fail because entity framework will realize the Results collection of the Person class as a foreign key from Results to Persons. The mapping will be the same as if you add a Person navigation property to the Result class.

如果你想人和结果有你有添加一个多一对多的关系的ICollection＆LT;＆人GT;人属性设置为结果类，使EF明白这一点。

If you want Person and Result to have a many-to-many relationship you have to add a ICollection<Person> Persons property to the Results class to make EF understand that.

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