Entity Framework Migrations - violation of referential integrity restrictions

Question

I struggled with this for a while and cannot find a solution for.

I have an MVC application that uses Entity Framework templates with repositories and work modules. I recently switched from using a network database (Sql Server 2008 R2, where the problem did not seem to exist) to a local database, and started using Entity Framework migrations to work with another developer and did not affect each other by making changes to our models .

My model looks like this:

[Table("Student")]
public class Student
{
    [Key]
    public int Id { get; set; }

    <... other fields ...>

    [Required(ErrorMessage = "A student type is required")]
    public int StudentTypeId { get; set; }

    [Required(ErrorMessage = "A student status is required")]
    public int StudentStatusId { get; set; }

    [ForeignKey("StudentTypeId")]
    public virtual StudentType StudentType { get; set; }

    [ForeignKey("StudentStatusId")]
    public virtual StudentStatus StudentStatus { get; set; }
}

Every time I try to update the StudentStatus property for Student, I get the following exception:

" , . ObjectContext . : : () "StudentStatus.Id" "Student.StudentStatusId" . "

.

student.StudentStatus = null;
student.StudentStatusId = 26;
_studentRepository.Update(student);
_unitOfWork.Commit();

StudentStatus:

var studentStatus = _studentStatusRepository.GetById(26);
student.StudentStatusId = 26;
student.StudentStatus = studentStatus;
_studentRepository.Update(student);
_unitOfWork.Commit();

DataContext.SaveChanges().

StudentType ( ) .

:

public virtual void Update(T entity)
{
    try
    {
        DataContext.Entry(entity).State = EntityState.Modified;
    }
    catch (Exception exception)
    {
        throw new EntityException(string.Format("Failed to update entity '{0}'", typeof(T).Name), exception);
    }
}

, EF Migrations , ( , , ). , .

, , , , ?

EDIT ( StudentStatus StudentStatusType)

[Table("StudentStatus")]
public class StudentStatus
{
    [Key]
    public int Id { get; set; }

    [Required(ErrorMessage = "Student status name is required")]
    [MaxLength(50, ErrorMessage = "Student status name cannot be longer than 50 characters")]
    public string Name { get; set; }

    public int StudentStatusTypeId { get; set; }

    [ForeignKey("StudentStatusTypeId")]
    public virtual StudentStatusType StudentStatusType { get; set; }
}

[Table("StudentStatusType")]
public class StudentStatusType
{
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
}

2

, , , SQL- Entity Framework:

DataContext.Database.Log = s => Debug.WriteLine(s); 

:

UPDATE [dbo].[Student]
SET <... some parameters ...>, [StudentStatusId] = @10, <... some parameters ...>
WHERE ([Id] = @14)

UPDATE [dbo].[Student]
SET <... some parameters ...>, [StudentStatusId] = @10, <... some parameters ...>
WHERE ([Id] = @14)

<... some parameters ...>

-- @10: '25' (Type = Int32)

-- @10: '25' (Type = Int32)

<... some parameters ...>

-- Executing at 12/01/2015 12:30:41 +00:00

-- Executing at 12/01/2015 12:30:41 +00:00

-- Completed in 0 ms with result: 1

-- Completed in 0 ms with result: 1

, EF 25, , 26? ? , , ?

Answer 1

Adimeus , .

StudentStatus StudentType ( Configuration.cs EF Migrations) - , ; , .

:

if (!_studentStatusRepository.GetAll().Any())
{
    var newStudentStatus = _studentStatusTypeRepository.Get(x => x.Name == "New");
    var activeStudentStatus = _studentStatusTypeRepository.Get(x => x.Name == "Active");
    var deletedStudentStatus = _studentStatusTypeRepository.Get(x => x.Name == "Deleted");

    var studentStatuses = new List<StudentStatus>
    {
        new StudentStatus {Name = "New", StudentStatusType = newStudentStatus, StudentStatusTypeId = newStudentStatus.Id},
        new StudentStatus {Name = "Awaiting Approval", StudentStatusType = activeStudentStatus, StudentStatusTypeId = activeStudentStatus.Id},
        new StudentStatus {Name = "Approved", StudentStatusType = activeStudentStatus, StudentStatusTypeId = activeStudentStatus.Id},
        new StudentStatus {Name = "Deleted", StudentStatusType = deletedStudentStatus, StudentStatusTypeId = deletedStudentStatus.Id},
        new StudentStatus {Name = "Reinstated", StudentStatusType = deletedStudentStatus, StudentStatusTypeId = deletedStudentStatus.Id}
    };

    foreach (var studentStatus in studentStatuses.ToList())
    {
        StudentStatus status = studentStatus;
        var dbStudentStatus = _studentStatusRepository.Get(x => x.Name == status.Name);
        if (dbStudentStatus == null)
        {
            _studentStatusRepository.Add(studentStatus);
        }
    }
    _unitOfWork.Commit();
}

EF Migrations Configuration.cs (, , ):

var studentStatuses = new List<StudentStatus>
{
    new StudentStatus
    {
        Name = "New",
        StudentStatusType = context.StudentStatusTypes.Single(x => x.Name == "New"),
        StudentStatusTypeId = context.StudentStatusTypes.Single(x => x.Name == "New").Id,
    },
    new StudentStatus
    {
        Name = "Awaiting Approval",
        StudentStatusType = context.StudentStatusTypes.Single(x => x.Name == "Active"),
        StudentStatusTypeId = context.StudentStatusTypes.Single(x => x.Name == "Active").Id,
    },
    new StudentStatus
    {
        Name = "Approved",
        StudentStatusType = context.StudentStatusTypes.Single(x => x.Name == "Active"),
        StudentStatusTypeId = context.StudentStatusTypes.Single(x => x.Name == "Active").Id,
    },
    new StudentStatus
    {
        Name = "Deleted",
        StudentStatusType = context.StudentStatusTypes.Single(x => x.Name == "Deleted"),
        StudentStatusTypeId = context.StudentStatusTypes.Single(x => x.Name == "Deleted").Id,
    },
    new StudentStatus
    {
        Name = "Reinstated",
        StudentStatusType = context.StudentStatusTypes.Single(x => x.Name == "Deleted"),
        StudentStatusTypeId = context.StudentStatusTypes.Single(x => x.Name == "Deleted").Id,
    }
};

studentStatuses.ForEach(x => context.StudentStatuses.AddOrUpdate(y => y.Name, x));

! StudentStatus. , . - , ; .

Answer 2

:

int StudentStatusType StudentStatusType.Id, [ForeignKey]. virtual StudentStatusType -property, EntityFramework .

[Table("StudentStatus")]
public class StudentStatus
{
    [Key]
    public int Id { get; set; }

    [Required(ErrorMessage = "Student status name is required")]
    [MaxLength(50, ErrorMessage = "Student status name cannot be longer than 50 characters")]
    public string Name { get; set; }

    [ForeignKey("StudentStatusType")] 
    public int StudentStatusTypeId { get; set; }
    public virtual StudentStatusType StudentStatusType { get; set; }
}

[Table("StudentStatusType")]
public class StudentStatusType
{
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
}

Answer 3

EF , StudentStatus Student. StudentStatus .

public virtual ICollection<Student> Students { get; set; }