Multiplicity constraint violated Entity framework 5

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.

public class Person : IPerson

    public int Id { get; set; }
    public string FirstName { get; set; }

    public string LastName { get; set; }

    public string Name
            return FirstName + " " + LastName;

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

The UserProfile class

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.


Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

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.

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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