Entity Framework save collection

Question

I have Entity Framework Code First models. When I try save collection of Accounts in one insert i get error message.

 public class User
{
    [Key]
    public int Usr_Id { get; set; }
    [Required]
    [MaxLength(35)]
    public string Name { get; set; }
    [Required]
    [MaxLength(35)]
    public string Surname { get; set; }
    [Required]
    [MaxLength(35)]
    public string Location { get; set; }        

    //NAVIGATION
    public User()
    {
        UserDevices = new List<UserDevice>();
    }

    public virtual ICollection<UserDevice> UserDevices { get; set; }

}

 public class UserDevice
{
    [Key]
    public int UsrDev_Id { get; set; }
    [Required]
    [MaxLength(50)]
    public string PurposeOfUse { get; set; }

    // NAVIGATION

    public UserDevice()
    {
        Accounts = new List<Account>();
    }

    //User can have many UserDevice
    public int Usr_Id { get; set; }        
    public virtual User User { get; set; }

    //UserDevice can have many Acoount
    public virtual ICollection<Account> Accounts { get; set; }

    //One to one
    public virtual SoftwareInformation SoftwareInformation { get; set; }
    public virtual HardwareInformation HardwareInformation { get; set; }
}

 public class Account
{
    [Key]
    public int Acc_Id { get; set; }
    public string Name { get; set; }

    //NAVIGATION

    //UserDevice can have many Account
    public int UsrDev_Id { get; set; }
    public virtual UserDevice UserDevice { get; set; }

}

Insert of new UserDevice

List<Account> accountsList = new List<Account>();

            foreach (var item in model.DeviceInformations.OS.Accounts)
            {
                accountsList.Add(new Account { Name = item.Name });
            }              


            _unitOfWork.UserDevices.Add(new UserDevice
            {
                Usr_Id = model.Usr_Id,
                PurposeOfUse = model.PurposeOfUse,

                HardwareInformation = new HardwareInformation
                {
                    MB_Manufacturer = model.DeviceInformations.Motherboard.Manufacturer,
                    MB_Model = model.DeviceInformations.Motherboard.Model,
                    MB_Name = model.DeviceInformations.Motherboard.Name,
                    MB_UUID = model.DeviceInformations.Motherboard.UUID,
                    CPU_Manufacturer = model.DeviceInformations.Processor.Manufacturer,
                    CPU_MaxClockSpeed = model.DeviceInformations.Processor.MaxClockSpeed,
                    CPU_Name = model.DeviceInformations.Processor.Name,
                },

                SoftwareInformation = new SoftwareInformation
                {
                    OS_Edition = model.DeviceInformations.OS.Edition,
                    OS_HostName = model.DeviceInformations.OS.HostName,
                    OS_Language = model.DeviceInformations.OS.Language,
                    OS_Platform = model.DeviceInformations.OS.Platform,
                    OS_ProductKey = model.DeviceInformations.OS.ProductKey,
                    OS_ServicePackVersion = model.DeviceInformations.OS.ServicePackVersion,
                    OS_Version = model.DeviceInformations.OS.Version
                }, 

                Accounts = accountsList
            });
            _unitOfWork.Commit();

Error message

{"Cannot insert the value NULL into column 'Acc_Id', table 'LICENSE_WATCHER_TEST.dbo.Accounts'; column does not allow nulls. INSERT fails.\r\nThe statement has been terminated."}

It happends when I try save Accout collection. Is there a way how to save Accouts collection in one Insert?

Answer 1

Acc_id is null on insert. I would expect that ID to be auto generated in cases like this. Is it possible that you have the Acc_id column on the Account Table set up as PK, but not an Identity column in the database?

That might cause the behavior that you are experiencing.