Question

I have been trying to understand why I am getting an exception when trying to use a stroed procedure for the purpose of inserting a record. I have a company table in the database with the columns Id(Guid), Name(nvarchar) and timestamp(datetime) .The Id column is a RowGuid. Also I am using SQL server 2005 and EF4

The stored procedure is

ALTER PROCEDURE [dbo].[InsertCompanySP]
  @companyName NVarChar(50),
  @timeStamp datetime
AS
BEGIN
SET NOCOUNT ON;
    Insert into dbo.Company(Name,TimeStamp) values (@companyName, @timeStamp)
select SCOPE_IDENTITY() as Id 
END

the code I am using to call this stored procedure is

using (var context = new testEntities())
        {
            try
            {
                Company c = new Company();
                c.Name = "abcd";
                c.TimeStamp = DateTime.Now;

                context.Companies.AddObject(c);
                context.SaveChanges();

                Console.WriteLine(c.Id);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Exception Occurred");
            }
        }

as you can guess, In the Entity Framework model’s Insert stored procedure mapping the companyName and timeStamp are bound to the Name and TimeStamp properties of my Company Entity and the Id is bound to the Id property of the Company Entity. If I go ahead and remove the result column binding , everything works fine (the stored procedure is called and no exception is thrown). When I have the result binding in place to return the Id of the added Company, I can still see the exact same stored procedure being called but it throws an exception saying

“A null store-generated value was returned for a non-nullable member ‘Id’ of type ‘testModel.Company’.”

I am assuming I might have something incorrect in my stored procedure with returning the Id of the inserted row but I am not able to figure it out. I also tried using the following in the stored procedure for returning the value of the Company Id inserted but I still get the same exception

select Id = @@IDENTITY

UPDATE:I forgot to mention that the Id is also marked with StoreGeneratedPattern = Identity in the EF

UPDATE: I solved the problem thanks to @olivehour.. modified my stored procedure to

ALTER PROCEDURE [dbo].[InsertCompanySP]
  @companyName NVarChar(50),
  @timeStamp datetime
AS
BEGIN
SET NOCOUNT ON;

DECLARE @TmpTable TABLE (Id uniqueidentifier);     

Insert into dbo.Company(Name,TimeStamp)
OUTPUT INSERTED.Id INTO @TmpTable  
values (@companyName, @timeStamp)

select Id  from @TmpTable

END

Answer 1

Have a look at this. You can’t use SCOPE_IDENTITY for Guids. If your primary key is clustered on the GUID, this could also be bad.