Entity Framework entities different keys are mapped to same row

Question

I am using Entity Framework , just updated a few changes from the database, then came accross this error: Problem in mapping fragments starting at lines 903, 1239:Two entities with possibly different keys are mapped to the same row. Ensure these two mapping fragments map both ends of the AssociationSet to the corresponding columns. Problem in mapping fragments starting at lines 903, 1239:Two entities with possibly different keys are mapped to the same row. Ensure these two mapping fragments map both ends of the AssociationSet to the corresponding columns.

I understand the problem, however, I dont know what the offending tables are. The database has more than 50 tables, and there are hundreds of relationships between them. I have no idea where to start. The Stack Trace:

[MappingException: 
Tracker.msl(903,10) : error 3034: Problem in mapping fragments starting at lines 903, 1239:Two entities with possibly different keys are mapped to the same row. Ensure these two mapping fragments map both ends of the AssociationSet to the corresponding columns.
]
   System.Data.Entity.Core.Mapping.ViewDictionary.SerializedGenerateViews(EntityContainerMapping entityContainerMap, Dictionary`2 resultDictionary) +193
   System.Data.Entity.Core.Mapping.ViewDictionary.SerializedGetGeneratedViews(EntityContainer container) +327
   System.Data.Entity.Core.Common.Utils.<>c__DisplayClass2.<Evaluate>b__0() +50
   System.Data.Entity.Core.Common.Utils.Result.GetValue() +154
   System.Data.Entity.Core.Common.Utils.Memoizer`2.Evaluate(TArg arg) +498
   System.Data.Entity.Core.Mapping.ViewDictionary.GetGeneratedView(EntitySetBase extent, MetadataWorkspace workspace, StorageMappingItemCollection storageMappingItemCollection) +1596
   System.Data.Entity.Core.Mapping.StorageMappingItemCollection.GetGeneratedView(EntitySetBase extent, MetadataWorkspace workspace) +62
   System.Data.Entity.Core.Metadata.Edm.MetadataWorkspace.GetGeneratedView(EntitySetBase extent) +128
   System.Data.Entity.Core.Query.PlanCompiler.PreProcessor.ExpandView(ScanTableOp scanTableOp, IsOfOp& typeFilter) +657
   System.Data.Entity.Core.Query.PlanCompiler.PreProcessor.ProcessScanTable(Node scanTableNode, ScanTableOp scanTableOp, IsOfOp& typeFilter) +229
   System.Data.Entity.Core.Query.PlanCompiler.PreProcessor.Visit(ScanTableOp op, Node n) +57
   System.Data.Entity.Core.Query.InternalTrees.ScanTableOp.Accept(BasicOpVisitorOfT`1 v, Node n) +47
   System.Data.Entity.Core.Query.InternalTrees.BasicOpVisitorOfT`1.VisitNode(Node n) +121
   System.Data.Entity.Core.Query.PlanCompiler.SubqueryTrackingVisitor.VisitChildren(Node n) +139
   System.Data.Entity.Core.Query.PlanCompiler.SubqueryTrackingVisitor.VisitRelOpDefault(RelOp op, Node n) +62
   System.Data.Entity.Core.Query.PlanCompiler.PreProcessor.Visit(FilterOp op, Node n) +295
   System.Data.Entity.Core.Query.InternalTrees.FilterOp.Accept(BasicOpVisitorOfT`1 v, Node n) +47
   System.Data.Entity.Core.Query.InternalTrees.BasicOpVisitorOfT`1.VisitNode(Node n) +121
   System.Data.Entity.Core.Query.PlanCompiler.SubqueryTrackingVisitor.VisitChildren(Node n) +139
   System.Data.Entity.Core.Query.PlanCompiler.SubqueryTrackingVisitor.VisitRelOpDefault(RelOp op, Node n) +62
   System.Data.Entity.Core.Query.InternalTrees.BasicOpVisitorOfT`1.VisitSortOp(SortBaseOp op, Node n) +47
   System.Data.Entity.Core.Query.InternalTrees.BasicOpVisitorOfT`1.Visit(ConstrainedSortOp op, Node n) +47
   System.Data.Entity.Core.Query.InternalTrees.ConstrainedSortOp.Accept(BasicOpVisitorOfT`1 v, Node n) +47
   System.Data.Entity.Core.Query.InternalTrees.BasicOpVisitorOfT`1.VisitNode(Node n) +121
   System.Data.Entity.Core.Query.PlanCompiler.SubqueryTrackingVisitor.VisitChildren(Node n) +139
   System.Data.Entity.Core.Query.InternalTrees.BasicOpVisitorOfNode.VisitDefault(Node n) +39
   System.Data.Entity.Core.Query.InternalTrees.BasicOpVisitorOfNode.VisitPhysicalOpDefault(PhysicalOp op, Node n) +44
   System.Data.Entity.Core.Query.InternalTrees.BasicOpVisitorOfT`1.Visit(PhysicalProjectOp op, Node n) +47
   System.Data.Entity.Core.Query.InternalTrees.PhysicalProjectOp.Accept(BasicOpVisitorOfT`1 v, Node n) +47
   System.Data.Entity.Core.Query.InternalTrees.BasicOpVisitorOfT`1.VisitNode(Node n) +121
   System.Data.Entity.Core.Query.PlanCompiler.PreProcessor.Process(Dictionary`2& tvfResultKeys) +112
   System.Data.Entity.Core.Query.PlanCompiler.PreProcessor.Process(PlanCompiler planCompilerState, StructuredTypeInfo& typeInfo, Dictionary`2& tvfResultKeys) +93
   System.Data.Entity.Core.Query.PlanCompiler.PlanCompiler.Compile(List`1& providerCommands, ColumnMap& resultColumnMap, Int32& columnCount, Set`1& entitySets) +170
   System.Data.Entity.Core.Query.PlanCompiler.PlanCompiler.Compile(DbCommandTree ctree, List`1& providerCommands, ColumnMap& resultColumnMap, Int32& columnCount, Set`1& entitySets) +111
   System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition..ctor(DbProviderFactory storeProviderFactory, DbCommandTree commandTree, DbInterceptionContext interceptionContext, IDbDependencyResolver resolver, BridgeDataReaderFactory bridgeDataReaderFactory, ColumnMapFactory columnMapFactory) +647

[EntityCommandCompilationException: An error occurred while preparing the command definition. See the inner exception for details.]
   System.Data.Entity.Core.EntityClient.Internal.EntityCommandDefinition..ctor(DbProviderFactory storeProviderFactory, DbCommandTree commandTree, DbInterceptionContext interceptionContext, IDbDependencyResolver resolver, BridgeDataReaderFactory bridgeDataReaderFactory, ColumnMapFactory columnMapFactory) +2623
   System.Data.Entity.Core.EntityClient.Internal.EntityProviderServices.CreateCommandDefinition(DbProviderFactory storeProviderFactory, DbCommandTree commandTree, DbInterceptionContext interceptionContext, IDbDependencyResolver resolver) +68
   System.Data.Entity.Core.EntityClient.Internal.EntityProviderServices.CreateDbCommandDefinition(DbProviderManifest providerManifest, DbCommandTree commandTree, DbInterceptionContext interceptionContext) +151
   System.Data.Entity.Core.Common.DbProviderServices.CreateCommandDefinition(DbCommandTree commandTree, DbInterceptionContext interceptionContext) +220
   System.Data.Entity.Core.Objects.Internal.ObjectQueryExecutionPlanFactory.CreateCommandDefinition(ObjectContext context, DbQueryCommandTree tree) +210
   System.Data.Entity.Core.Objects.Internal.ObjectQueryExecutionPlanFactory.Prepare(ObjectContext context, DbQueryCommandTree tree, Type elementType, MergeOption mergeOption, Boolean streaming, Span span, IEnumerable`1 compiledQueryParameters, AliasGenerator aliasGenerator) +255
   System.Data.Entity.Core.Objects.ELinq.ELinqQueryState.GetExecutionPlan(Nullable`1 forMergeOption) +2430
   System.Data.Entity.Core.Objects.<>c__DisplayClass7.<GetResults>b__6() +83
   System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction(Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess) +448
   System.Data.Entity.Core.Objects.<>c__DisplayClass7.<GetResults>b__5() +271
   System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Func`1 operation) +251
   System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption) +648
   System.Data.Entity.Core.Objects.ObjectQuery`1.<System.Collections.Generic.IEnumerable<T>.GetEnumerator>b__0() +68
   System.Data.Entity.Internal.LazyEnumerator`1.MoveNext() +68
   System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source) +4098209
   System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.<GetElementFunction>b__2(IEnumerable`1 sequence) +83
   System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.ExecuteSingle(IEnumerable`1 query, Expression queryRoot) +107
   System.Data.Entity.Core.Objects.ELinq.ObjectQueryProvider.System.Linq.IQueryProvider.Execute(Expression expression) +197
   System.Data.Entity.Internal.Linq.DbQueryProvider.Execute(Expression expression) +155
   System.Linq.Queryable.SingleOrDefault(IQueryable`1 source, Expression`1 predicate) +287
   Tracker.Implementations.UserDetails.Tracker.Infrastructure.IUserDetails.getUser(String Email) +550
   TrackerV3MVC.Controllers.HomeController.Index() in c:\WorkSpace\Entire Solution\TrackerV3MVC\Controllers\HomeController.cs:32
   lambda_method(Closure , ControllerBase , Object[] ) +101
   System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters) +14
   System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters) +211
   System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters) +27
   System.Web.Mvc.Async.<>c__DisplayClass42.<BeginInvokeSynchronousActionMethod>b__41() +28
   System.Web.Mvc.Async.<>c__DisplayClass8`1.<BeginSynchronous>b__7(IAsyncResult _) +10
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) +48
   System.Web.Mvc.Async.<>c__DisplayClass39.<BeginInvokeActionMethodWithFilters>b__33() +57
   System.Web.Mvc.Async.<>c__DisplayClass4f.<InvokeActionMethodFilterAsynchronously>b__49() +223
   System.Web.Mvc.Async.<>c__DisplayClass37.<BeginInvokeActionMethodWithFilters>b__36(IAsyncResult asyncResult) +10
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) +48
   System.Web.Mvc.Async.<>c__DisplayClass2a.<BeginInvokeAction>b__20() +24
   System.Web.Mvc.Async.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult) +102
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +57
   System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +43
   System.Web.Mvc.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) +14
   System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +57
   System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +47
   System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
   System.Web.Mvc.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) +25
   System.Web.Mvc.Async.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) +23
   System.Web.Mvc.Async.WrappedAsyncResult`1.End() +62
   System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +47
   System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9514928
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

Answer 1

Sometimes Entity Framework does not give precise indications about errors. And the update model tool does not work as well as it should....

In cases like these I usually clear the edmx file (delete all the tables) and add them again.

If that's not possible, open your edmx file (as an xml file) and navigate to the lines specified in the error, you might find the source of your troubles