Untyped NULL constant value is not supported for CASE statement

[Eric_08]

I'm getting

Code: Select all

System.NotImplementedException: Untyped NULL constant value is not supported.

error when DevArt attempts to build Oracle CASE statement in the query from the following .NET code:

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            var query =
                from a in some_table
                let j = (a.Column1 == "0" ? a.Column1 : null) // <-- Fails because of null value!
                select j;

            var h = await query.FirstOrDefaultAsync();

Full stack trace:

Code: Select all

System.NotImplementedException: Untyped NULL constant value is not supported.
   at Devart.Common.Entity.dc.a(SqlConstantExpression A_0)
   at Microsoft.EntityFrameworkCore.Query.SqlExpressionVisitor.VisitExtension(Expression extensionExpression)
   at System.Linq.Expressions.Expression.Accept(ExpressionVisitor visitor)
   at Microsoft.EntityFrameworkCore.Query.QuerySqlGenerator.VisitCase(CaseExpression caseExpression)
   at Microsoft.EntityFrameworkCore.Query.SqlExpressionVisitor.VisitExtension(Expression extensionExpression)
   at System.Linq.Expressions.Expression.Accept(ExpressionVisitor visitor)
   at Microsoft.EntityFrameworkCore.Query.QuerySqlGenerator.VisitProjection(ProjectionExpression projectionExpression)
   at Microsoft.EntityFrameworkCore.Query.SqlExpressionVisitor.VisitExtension(Expression extensionExpression)
   at System.Linq.Expressions.Expression.Accept(ExpressionVisitor visitor)
   at Microsoft.EntityFrameworkCore.Query.QuerySqlGenerator.<VisitSelect>b__18_0(ProjectionExpression e)
   at Microsoft.EntityFrameworkCore.Query.QuerySqlGenerator.GenerateList[T](IReadOnlyList`1 items, Action`1 generationAction, Action`1 joinAction)
   at Microsoft.EntityFrameworkCore.Query.QuerySqlGenerator.VisitSelect(SelectExpression selectExpression)
   at Devart.Common.Entity.dc.c(SelectExpression A_0)
   at Devart.Data.Oracle.Entity.bg.a(SelectExpression A_0)
   at Microsoft.EntityFrameworkCore.Query.QuerySqlGenerator.GetCommand(SelectExpression selectExpression)
   at Devart.Common.Entity.dc.e(SelectExpression A_0)
   at Microsoft.EntityFrameworkCore.Query.Internal.RelationalCommandCache.GetRelationalCommand(IReadOnlyDictionary`2 parameters)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.AsyncEnumerator.InitializeReaderAsync(DbContext _, Boolean result, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.AsyncEnumerator.MoveNextAsync() Untyped NULL constant value is not supported.

The above error occurs when using new DevArt driver 9.10.925 with .NET Core 3.1.1/EF Core 3.1.1. However, everything works correctly when the code was running on NET Core 2.2/EF Core 2.2.6 using DevArt driver 9.9.887, so it appears that upgrading to .NET Core 3.1/EF Core 3.1 is causing this issue.

[Eric_08]

Any update?

[Shalex]

We have reproduced the issue and will notify you when it is fixed.

[Eric_08]

Great. When can we expect the new DevArt build with fixes to this issue and other .NET Core 3.1/EF Core 3.1 issues? I need to upgrade my application to run .NET Core 3.1/EF Core 3.1, and due to various outstanding issues with DevArt driver, I'm unable to do so.

Thanks,
Eric

[Shalex]

We will provide the internal build with fixes after the bug you reported is solved. We are working on it.

We plan to release the new public builds in several weeks.

[Shalex]

The bug with using NULL constant values in EF Core 3 is fixed. We will notify you when the new public build is available for download.

[Shalex]

dotConnect for Oracle v9.11.951 is released: viewtopic.php?f=1&t=39884.