Problem with inserting using linq-to-entities

Question

Hi I'm having trouble solving this error. Any help on the problem would be much appreciated, thanks!

Error message:
Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.

Whenever I try to add a Laptop/Desktop, I get the above error message.
Everything works fine when running locally, but not on dev. The website and service/database are on two different dev boxes.

Tables:
Computer: ComputerID, UserID, HardwareName, Brand, IsDefaultDevice
Desktop: ComputerID,  MonitorWidth
Laptop: ComputerID, BatteryLife

generated sql:
exec sp_executesql N'insert [ScratchPad].[Computer]([UserID], [ComputerName], [Brand], [IsDefaultDevice])
values (@0, @1, @2, @3)
select [ComputerID]
from [ScratchPad].[Computer]
where @@ROWCOUNT > 0 and [ComputerID] = scope_identity()',N'@0 bigint,@1 nvarchar(19),@2 int,@3 bit',@0=2,@1=N'Computer666',@2=1,@3=0


using(var context = new MyDatabaseEntities())
{
       User user = context.Users.FirstOrDefault(x => x.UserID == userId);
       entityToAdd.User = user;
       bool hasOthers = context.Computers.Any(x=>x.User.UserID == userId);
       if(!hasOthers && !entityToAdd.IsDefaultDevice)
            entityToAdd.IsDefaultDevice = true;
       entityToAdd.BrandReference.EntityKey = Brand.GetDellProviderKey();
       context.AddToComputers(entityToAdd);
       context.SaveChanges();
}

Here is the stack trace:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[FaultException`1: Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.]
   System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) +10259418
   System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) +539
   myWebPortal.Repositories.UserServiceRef.IUserService.AddComputer(Int64 userId, Computer toAdd) +0
   myWebPortal.Repositories.UserServiceRef.UseServiceClient.AddComputer(Int64 userId, Computer toAdd) in c:\users\katelyn\documents\my web project\myWebPortal.repositories\service references\userserviceref\reference.cs:1282
   myWebPortal.Repositories.UserAccountRepository.AddComputer(Int64 userId, Computer computer) in C:\Users\katelyn\Documents\my Web Project\myWebPortal.Repositories\UserRepository.cs:238
   myWebPortal.Web.Controllers.ComputerController.AddComputer(ComputerModel model) in C:\Users\katelyn\Documents\my Web Project\myWebPortal.Web\Controllers\ComputerController.cs:71
   lambda_method(ExecutionScope , ControllerBase , Object[] ) +69
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +236
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +31
   System.Web.Mvc.<>c__DisplayClassd.<InvokeActionMethodWithFilters>b__a() +85
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation) +632195
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +288
   System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +630660
   System.Web.Mvc.Controller.ExecuteCore() +125
   System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__4() +48
   System.Web.Mvc.Async.<>c__DisplayClass1.<MakeVoidDelegate>b__0() +21
   System.Web.Mvc.Async.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _) +15
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +85
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +51
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +454
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +263

Also when trying to add a Laptop/Desktop, sometimes a Computer row would be inserted but not a Laptop/Desktop row.

Answer 1

Where are you instantiating/initialising entityToAdd?

Can you confirm the foreign key constraints and primary key information (auto-increment, type, etc.) It seems that the insert is failing for some reason which is being caught by the incorrect number of rows affected.

try running the SQL yourself from within sql management console - do you get any errors? is the record inserted correctly?

You may also want to ensure there are no triggers or similar on the table which may be causing issues.