Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby seb1487 » Thu 30 Jun 2016 07:33

Hi,
I wanted to test Devart dotConnect Professional with Entity Framework Core 1.
But SaveChanges() throws a System.NullReferenceException.

Full Exception:
Code: Select all
System.NullReferenceException: Object reference not set to an instance to an object.
   at Devart.Common.Entity.c.q()
   at Microsoft.EntityFrameworkCore.Storage.RelationalLoggerExtensions.<>c__DisplayClass0_0.<LogCommandExecuted>b__0()
   at Microsoft.EntityFrameworkCore.Storage.RelationalLoggerExtensions.LogInformation[TState](ILogger logger, RelationalLoggingEventId eventId, Func`1 state, Func`2 formatter)
   at Microsoft.EntityFrameworkCore.Storage.RelationalLoggerExtensions.LogCommandExecuted(ISensitiveDataLogger logger, DbCommand command, Int64 startTimestamp, Int64 currentTimestamp)
   at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.Execute(IRelationalConnection connection, String executeMethod, IReadOnlyDictionary`2 parameterValues, Boolean openConnection, Boolean closeConnection)
   at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalCommand.ExecuteReader(IRelationalConnection connection, IReadOnlyDictionary`2 parameterValues, Boolean manageConnection)
   at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)
   --- Ende der internen Ausnahmestapelüberwachung ---
   at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)
   at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.Execute(IEnumerable`1 commandBatches, IRelationalConnection connection)
   at Microsoft.EntityFrameworkCore.Storage.RelationalDatabase.SaveChanges(IReadOnlyList`1 entries)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(IReadOnlyList`1 entriesToSave)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Microsoft.EntityFrameworkCore.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)


Source: "Devart.Data.Oracle.Entity.EFCore"

Connection string:
Code: Select all
"Direct=true; Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=192.168.1.1)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=MyService))); User Id=UserId; Password=Password;"

Could you tell me why the error happen and how to solve it?
seb1487
 
Posts: 18
Joined: Fri 24 Jun 2016 10:27

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Fri 01 Jul 2016 16:38

The current (9.1.45) build of dotConnect for Oracle supports Entity Framework Core RC2. To use it, either add the Devart EF Core Model item (via the Add > New Item > Data menu of project in Solution Explorer) to make Entity Developer to add the Entity Framework Core RC2 packages in your project automatically, or install RC2 packages manually (Package source: https://www.nuget.org/api/v2/):
> Install-Package Microsoft.EntityFrameworkCore.Relational -PreRelease

The EF Core RTM support will be included in the next public build of dotConnect for Oracle. We will notify you when it is available for download.
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Thu 07 Jul 2016 17:33

Entity Framework Core 1.0 RTM is supported in the newest (9.1.55) build of dotConnect for Oracle: https://www.devart.com/dotconnect/oracle/revision_history.html.
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby seb1487 » Fri 08 Jul 2016 11:34

Thanks Shalex,
with 9.1.55 it works on Entity Framework Core 1.0 RTM, but i have found new Bugs.

1) Triggers are created with a carriage return on end. Oracle 10 cannot compile this triggers. (without works)

2) If a query with Enums is created, it doesn’t work. e.g.:
Code: Select all
context.Products.Where(o => o.Type == MyEnum.Software).ToList();


Workaround:
Code: Select all
var enumValue = (int)MyEnum.Software;
context.Products.Where(o => (int)o.Type == enumValue).ToList();


3) If a query with objects is created, it doesn’t work (possibly the same)
Code: Select all
var productCategory = context.ProductCategories.FirstOrDefault();
var product = context.Products.Where(o => o.CategoryId == productCategory.Id).ToList(); <-- Error


Workaround:
Code: Select all
var productCategory = context.ProductCategories.FirstOrDefault();
var productCategoryId = productCategory.Id;
var product = context.Products.Where(o => o.CategoryId == productCategoryId).ToList(); <-- Works
seb1487
 
Posts: 18
Joined: Fri 24 Jun 2016 10:27

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Wed 13 Jul 2016 16:45

Thank you for your report. We will notify you when the issues are fixed.
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Mon 18 Jul 2016 14:44

seb1487 wrote:2) If a query with Enums is created, it doesn’t work. e.g.:
Code: Select all
context.Products.Where(o => o.Type == MyEnum.Software).ToList();

Workaround:
Code: Select all
var enumValue = (int)MyEnum.Software;
context.Products.Where(o => (int)o.Type == enumValue).ToList();
2. Please specify:
a) the exact text of the error and its full stack trace
b) the SQL generated by the provider (check via dbMonitor)

seb1487 wrote:3) If a query with objects is created, it doesn’t work (possibly the same)
Code: Select all
var productCategory = context.ProductCategories.FirstOrDefault();
var product = context.Products.Where(o => o.CategoryId == productCategory.Id).ToList(); <-- Error

Workaround:
Code: Select all
var productCategory = context.ProductCategories.FirstOrDefault();
var productCategoryId = productCategory.Id;
var product = context.Products.Where(o => o.CategoryId == productCategoryId).ToList(); <-- Works
3. Please specify:
a) the exact text of the error and its full stack trace
b) the SQL generated by the provider (check via dbMonitor)
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby seb1487 » Tue 19 Jul 2016 07:05

Hi Shalex,
here are the asked informations.
2)
New knowledge:
Exception throws only if the enum value is passed into the function.
Code: Select all
public IEnumerable<Products> Get(MyEnum type)
{
   return context.Products.Where(o => o.Type == type).ToList();
}

Throws:
Code: Select all
System.InvalidOperationException occurred
  HResult=-2146233079
  Message=Rewriting child expression from type 'xxx.MyEnum' to type 'System.Int32' is not allowed, because it would change the meaning of the operation. If this is intentional, override 'VisitUnary' and change it to allow this rewrite.
  Source=System.Core
  StackTrace:
       at System.Linq.Expressions.ExpressionVisitor.ValidateChildType(Type before, Type after, String methodName)
       at System.Linq.Expressions.ExpressionVisitor.ValidateUnary(UnaryExpression before, UnaryExpression after)
       at System.Linq.Expressions.ExpressionVisitor.VisitBinary(BinaryExpression node)
       at System.Data.Common.CommandTrees.a.VisitBinary(BinaryExpression expression)
       at System.Data.Common.CommandTrees.a.b(SelectExpression A_0)
       at System.Data.Common.CommandTrees.b.b(SelectExpression A_0)
       at System.Data.Common.CommandTrees.a.c(SelectExpression A_0)
       at Microsoft.EntityFrameworkCore.Query.Expressions.SelectExpression.Accept(ExpressionVisitor visitor)
       at System.Linq.Expressions.ExpressionVisitor.VisitAndConvert[T](T node, String callerName)
       at Devart.Data.Oracle.Entity.z.a(SelectExpression A_0)
       at Microsoft.EntityFrameworkCore.Query.Expressions.SelectExpression.CreateDefaultQuerySqlGenerator()
       at Microsoft.EntityFrameworkCore.Query.Internal.ShaperCommandContext.GetRelationalCommand(IReadOnlyDictionary`2 parameters)
       at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable.Enumerator.MoveNext()
       at Microsoft.EntityFrameworkCore.Query.QueryMethodProvider.<_GroupJoin>d__26`4.MoveNext()
       at System.Linq.Enumerable.<SelectManyIterator>d__22`3.MoveNext()
       at System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
       at System.Linq.Lookup`2.Create[TSource](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
       at System.Linq.GroupedEnumerable`3.GetEnumerator()
       at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
       at Microsoft.EntityFrameworkCore.Query.Internal.LinqOperatorProvider.ExceptionInterceptor`1.EnumeratorExceptionInterceptor.MoveNext()
       at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
       at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
       at xxx.<Get>d__5.MoveNext() in xxx.cs:line 60
  InnerException:

SQL:
Code: Select all
No SQL generated.

3)
Code: Select all
var productCategory = context.ProductCategories.FirstOrDefault();
var product = context.Products.Where(o => o.CategoryId == productCategory.Id).ToList();

Throws:
Code: Select all
System.InvalidOperationException occurred
  HResult=-2146233079
  Message=Unexpected primitive type kind 'a'.
  Source=Devart.Data.Oracle.Entity.EFCore
  StackTrace:
       bei Devart.Common.Entity.cb.a(ck A_0)
       bei Devart.Common.Entity.b.f()
       bei System.Linq.Expressions.Expression.GetEqualityComparisonOperator(ExpressionType binaryType, String opName, Expression left, Expression right, Boolean liftToNull)
       bei System.Linq.Expressions.Expression.Equal(Expression left, Expression right, Boolean liftToNull, MethodInfo method)
       bei System.Linq.Expressions.BinaryExpression.Update(Expression left, LambdaExpression conversion, Expression right)
       bei System.Linq.Expressions.ExpressionVisitor.VisitBinary(BinaryExpression node)
       bei System.Data.Common.CommandTrees.a.VisitBinary(BinaryExpression expression)
       bei System.Linq.Expressions.ExpressionVisitor.VisitBinary(BinaryExpression node)
       bei System.Data.Common.CommandTrees.a.VisitBinary(BinaryExpression expression)
       bei System.Linq.Expressions.ExpressionVisitor.VisitBinary(BinaryExpression node)
       bei System.Data.Common.CommandTrees.a.VisitBinary(BinaryExpression expression)
       bei System.Data.Common.CommandTrees.a.b(SelectExpression A_0)
       bei System.Data.Common.CommandTrees.b.b(SelectExpression A_0)
       bei System.Data.Common.CommandTrees.a.c(SelectExpression A_0)
       bei Microsoft.EntityFrameworkCore.Query.Expressions.SelectExpression.Accept(ExpressionVisitor visitor)
       bei System.Linq.Expressions.ExpressionVisitor.VisitAndConvert[T](T node, String callerName)
       bei Devart.Data.Oracle.Entity.z.a(SelectExpression A_0)
       bei Microsoft.EntityFrameworkCore.Query.Expressions.SelectExpression.CreateDefaultQuerySqlGenerator()
       bei Microsoft.EntityFrameworkCore.Query.Internal.ShaperCommandContext.GetRelationalCommand(IReadOnlyDictionary`2 parameters)
       bei Microsoft.EntityFrameworkCore.Query.Internal.AsyncQueryingEnumerable.AsyncEnumerator.<MoveNext>d__8.MoveNext()
    --- Ende der Stapelüberwachung vom vorhergehenden Ort, an dem die Ausnahme ausgelöst wurde ---
       bei System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
       bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
       bei System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
       bei Microsoft.EntityFrameworkCore.Query.Internal.AsyncLinqOperatorProvider.<_FirstOrDefault>d__82`1.MoveNext()
    --- Ende der Stapelüberwachung vom vorhergehenden Ort, an dem die Ausnahme ausgelöst wurde ---
       bei System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
       bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
       bei System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
       bei Microsoft.EntityFrameworkCore.Query.Internal.TaskResultAsyncEnumerable`1.Enumerator.<MoveNext>d__3.MoveNext()
    --- Ende der Stapelüberwachung vom vorhergehenden Ort, an dem die Ausnahme ausgelöst wurde ---
       bei System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
       bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
       bei System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
       bei Microsoft.EntityFrameworkCore.Query.Internal.AsyncLinqOperatorProvider.ExceptionInterceptor`1.EnumeratorExceptionInterceptor.<MoveNext>d__5.MoveNext()
    --- Ende der Stapelüberwachung vom vorhergehenden Ort, an dem die Ausnahme ausgelöst wurde ---
       bei System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
       bei System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
       bei System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
       bei xxx.<Get>d__3.MoveNext() in xxx.cs:Zeile 49.
  InnerException:

SQL:
Code: Select all
No SQL generated.
seb1487
 
Posts: 18
Joined: Fri 24 Jun 2016 10:27

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Tue 19 Jul 2016 10:35

Thank you for the additional information. We are investigating the issue.
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Fri 22 Jul 2016 07:54

The new build of dotConnect for Oracle 9.1.67 is available for download now. It includes the following fixes:
  • The bug with generating triggers for Oracle 9/10/11 by EF Core Code-First migrations is fixed
  • The bug with convertation of enum values in parameters when using EF Core is fixed
Please try v9.1.67 and notify us about the result.
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby seb1487 » Fri 22 Jul 2016 13:21

Hi Shalex,
1 and 2 are fixed and working.
3 is still open.
seb1487
 
Posts: 18
Joined: Fri 24 Jun 2016 10:27

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Fri 22 Jul 2016 13:35

seb1487 wrote:3 is still open.
The investigation is in progress. We will notify you about the result.
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Thu 11 Aug 2016 15:28

seb1487 wrote:3 is still open.
The bug with long parameter names in EF Core is fixed in the newest (9.1.82) build of dotConnect for Oracle. Please try it and notify us about the result.
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby seb1487 » Thu 18 Aug 2016 07:10

Hi Shalex,
the BugFix did not work. But the problem exists now only if the FK is nullable.

Democode can be downloaded here.
seb1487
 
Posts: 18
Joined: Fri 24 Jun 2016 10:27

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Tue 23 Aug 2016 11:35

Thank you for your report. We have reproduced the "Unexpected primitive type kind 'a'." issue and are investigating it. We will notify you about the result.
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

Re: Entity Framework Core 1.0 throws System.NullReferenceException by SaveChanges

Postby Shalex » Fri 02 Sep 2016 14:34

The bug with nullable parameters in EF Core is fixed in the newest (9.1.97) build of dotConnect for Oracle: http://forums.devart.com/viewtopic.php?f=1&t=34216.
Shalex
Devart Team
 
Posts: 7616
Joined: Thu 14 Aug 2008 12:44

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