Entity Framework - Problem with querying nullable column

Question

I have a problem querying data from a table with a nullable tinyint column.
The problem seems to be that the query is generated as:

AND ( CAST( [Extent1].[PositionEffect] AS int) = @p__linq__3)

=> @p__linq__3 = NULL

If i run that query manually it doesn't turn up any results. However, when I replace the query with:

AND ([Extent1].[PositionEffect] IS @p__linq__3)

it turns up the expected results.
My C# query looks like this:

 context.Allocations.Where(x => ... && x.PositionEffect == (byte?) positionEffect)

So, why is the entity framework generating the incorrect query here and is there any way to fix this?

Thanks,

Tom

Does this social.msdn.microsoft.com/forums/en-US/linqprojectgeneral/… shed any light on the issue? — Will A
– Will A, Commented Jul 8, 2010 at 23:01
thanks, yes this did help, though it was for linq to sql and not entity framework (object.Equals does not work in entity framework) and I had to resort to this nasty piece of code: (positionEffect == null ? x.PositionEffect == null : x.PositionEffect == (byte?)positionEffect) — TJF
– TJF, Commented Jul 9, 2010 at 13:12

TJF · Accepted Answer · 2010-07-09 13:13:30Z

1

as Will A pointed out, this seems to be a reported bug in Entity Framework and the workaround to generate the correct query is:

 (positionEffect == null ? x.PositionEffect == null : x.PositionEffect == (byte?)positionEffect)

answered Jul 9, 2010 at 13:13

TJF

2,2586 gold badges29 silver badges43 bronze badges

Sign up to request clarification or add additional context in comments.

1 Answer 1