多重约束违反了实体框架5

Question

您好我有3个类Person,UserProfile(它继承Person)和Results,一个Person可以有一个或多个结果,当我尝试将ia结果添加到一个人时,我得到标题中提到的错误,我的类是下面的.任何帮助,将不胜感激.

[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; }
}

UserProfile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);
}

每当调用此功能后我都会打电话 _ctx.SaveChanges()

我得到了一个错误的错误

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

谢谢.

Answer 1

您是否尝试将其添加Result到多个用户？

在这种情况下,这将失败,因为实体框架将实现Results的集合Person类来自于外键Results来Persons.映射将与Person向Result类中添加导航属性相同.

如果你想要Person并Result拥有多对多的关系,你必须ICollection<Person> Persons在Results类中添加一个属性,以使EF了解这一点.