Multiplicity constraint violated Entity framework 5

asp.net asp.net-mvc c# entity-framework sql-server

Question

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; }
}

The UserProfile class

[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; }
}

The result class

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; }
}

The problem function

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

Whenever after calling this function i call _ctx.SaveChanges()

I get the fallowing error

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

Thank you.

1
7
11/17/2013 5:45:06 PM

Accepted Answer

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

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.

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.

21
11/17/2013 5:49:26 PM


Related Questions





Related

Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow
Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow