Question

I was using SQL Server Compact Edition (local-database) for my application. But while I was using the entity framework, I kept experiencing a very annoying UpdateException. My database only has two small tables with a foreign key relationship linking them together. So I am asking if there is any alternative to a database? Or is that the only option?
UPDATE:
Here is the EDMX map.
Here is the stacktrace for the exception:
System.Windows.Markup.XamlParseException was unhandled
Message=Cannot create instance of 'MainWindow' defined in assembly 'AssignmentOrganizer, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. Exception has been thrown by the target of an invocation. Error in markup file 'AssignmentOrganizer;component/MainWindow.xaml' Line 1 Position 9.
Source=PresentationFramework
LineNumber=1
LinePosition=9
StackTrace:
at System.Windows.Markup.XamlParseException.ThrowException(String message, Exception innerException, Int32 lineNumber, Int32 linePosition, Uri baseUri, XamlObjectIds currentXamlObjectIds, XamlObjectIds contextXamlObjectIds, Type objectType)
at System.Windows.Markup.XamlParseException.ThrowException(ParserContext parserContext, Int32 lineNumber, Int32 linePosition, String message, Exception innerException)
at System.Windows.Markup.BamlRecordReader.ThrowExceptionWithLine(String message, Exception innerException)
at System.Windows.Markup.BamlRecordReader.CreateInstanceFromType(Type type, Int16 typeId, Boolean throwOnFail)
at System.Windows.Markup.BamlRecordReader.GetElementAndFlags(BamlElementStartRecord bamlElementStartRecord, Object& element, ReaderFlags& flags, Type& delayCreatedType, Int16& delayCreatedTypeId)
at System.Windows.Markup.BamlRecordReader.BaseReadElementStartRecord(BamlElementStartRecord bamlElementRecord)
at System.Windows.Markup.BamlRecordReader.ReadElementStartRecord(BamlElementStartRecord bamlElementRecord)
at System.Windows.Markup.BamlRecordReader.ReadRecord(BamlRecord bamlRecord)
at System.Windows.Markup.BamlRecordReader.Read(Boolean singleRecord)
at System.Windows.Markup.TreeBuilderBamlTranslator.ParseFragment()
at System.Windows.Markup.TreeBuilder.Parse()
at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
at System.Windows.Application.LoadBamlStreamWithSyncInfo(Stream stream, ParserContext pc)
at System.Windows.Application.LoadComponent(Uri resourceLocator, Boolean bSkipJournaledProperties)
at System.Windows.Application.DoStartup()
at System.Windows.Application.<.ctor>b__0(Object unused)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
at System.Windows.Threading.DispatcherOperation.InvokeImpl()
at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
at System.Threading.ExecutionContext.runTryCode(Object userData)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Windows.Threading.DispatcherOperation.Invoke()
at System.Windows.Threading.Dispatcher.ProcessQueue()
at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter)
at System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg)
at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
at System.Windows.Threading.Dispatcher.Run()
at System.Windows.Application.RunDispatcher(Object ignore)
at System.Windows.Application.RunInternal(Window window)
at System.Windows.Application.Run(Window window)
at System.Windows.Application.Run()
at AssignmentOrganizer.App.Main() in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\AssignmentOrganizer\AssignmentOrganizer\obj\x86\Debug\App.g.cs:line 0
at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException: System.Reflection.TargetInvocationException
Message=Exception has been thrown by the target of an invocation.
Source=mscorlib
StackTrace:
at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandle& ctor, Boolean& bNeedSecurityCheck)
at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean fillCache)
at System.RuntimeType.CreateInstanceImpl(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean fillCache)
at System.Activator.CreateInstance(Type type, Boolean nonPublic)
at System.Windows.Markup.BamlRecordReader.CreateInstanceFromType(Type type, Int16 typeId, Boolean throwOnFail)
InnerException: System.Data.UpdateException
Message=An error occurred while updating the entries. See the InnerException for details.
Source=System.Data.Entity
StackTrace:
at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)
at System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache)
at System.Data.Objects.ObjectContext.SaveChanges(Boolean acceptChangesDuringSave)
at System.Data.Objects.ObjectContext.SaveChanges()
at AssignmentOrganizer.App_Data.AssignmentRepository.CreateAssignment(Assignment assignmentToCreate) in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\AssignmentOrganizer\AssignmentOrganizer\App_Data\AssignmentRepository.cs:line 20
at AssignmentOrganizer.MainWindow..ctor() in C:\Users\Mohit\Documents\Visual Studio 2010\Projects\AssignmentOrganizer\AssignmentOrganizer\MainWindow.xaml.cs:line 34
InnerException: System.Data.EntityCommandCompilationException
Message=An error occurred while preparing the command definition. See the inner exception for details.
Source=System.Data.Entity
StackTrace:
at System.Data.Mapping.Update.Internal.UpdateTranslator.CreateCommand(DbModificationCommandTree commandTree)
at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.CreateCommand(UpdateTranslator translator, Dictionary2 identifierValues)
at System.Data.Mapping.Update.Internal.DynamicUpdateCommand.Execute(UpdateTranslator translator, EntityConnection connection, Dictionary2 identifierValues, List1 generatedValues)
at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter)
InnerException: System.NotSupportedException
Message=Server-generated keys and server-generated values are not supported by SQL Server Compact.
Source=System.Data.SqlServerCe.Entity
StackTrace:
at System.Data.SqlServerCe.SqlGen.DmlSqlGenerator.GenerateReturningSql(StringBuilder commandText, DbModificationCommandTree tree, ExpressionTranslator translator, DbExpression returning)
at System.Data.SqlServerCe.SqlGen.DmlSqlGenerator.GenerateInsertSql(DbInsertCommandTree tree, List1& parameters, Boolean isLocalProvider)
at System.Data.SqlServerCe.SqlGen.SqlGenerator.GenerateSql(DbCommandTree tree, List1& parameters, CommandType& commandType, Boolean isLocalProvider)
at System.Data.SqlServerCe.SqlCeProviderServices.CreateCommand(DbProviderManifest providerManifest, DbCommandTree commandTree)
at System.Data.SqlServerCe.SqlCeProviderServices.CreateDbCommandDefinition(DbProviderManifest providerManifest, DbCommandTree commandTree)
at System.Data.Common.DbProviderServices.CreateCommandDefinition(DbCommandTree commandTree)
at System.Data.Common.DbProviderServices.CreateCommand(DbCommandTree commandTree)
at System.Data.Mapping.Update.Internal.UpdateTranslator.CreateCommand(DbModificationCommandTree commandTree)
InnerException:
`

Answer 1

There are always alternatives. The question is whether they’re better than a database. You could store your data in XML, or your own file format, etc. Then you’d have to write appropriate querying, updating code etc. That may be fine – but we can’t possibly say without more information.

However, before even considering another solution, I would get to the bottom of why you’re seeing an exception. You may well have some behavior you didn’t really anticipate which could equally hurt you when you’ve changed your storage layer – and it may well be harder to diagnose at that point. Once you’ve worked out why your current approach isn’t working, you’ll be in a much better position to know whether or not it’s worth changing.