Mapping a sproc that returns a scalar value

Question

When I use "Create Function Import" in EF4 to map a sproc that returns a bigint, I get a function that returns an ObjectResult<long?>, although the Column Information displays "nullable - false". Why does it make the result nullable, and is there any way to get just an ObjectResult<long>? (Actually it's just a single long that I want, not a collection of longs, but that seems to be impossible in the Entity Framework, although in Linq to SQL it was simple.)

Answer 1

Can we see the sproc code?  Then I can try to reproduce it.

Answer 2

Sure. The sproc retrieves the row count for the specified table from DMVs.

CREATE PROCEDURE [dbo].[GetRowCount] 
(
	@tableName nvarchar(100)
)
AS
		select row_count
		 from sys.dm_db_partition_stats d, sys.objects o
		 where d.index_id < 2 and o.name = @tableName and d.object_id = o.object_id
GO

Answer 3

Yes totally...Same thing here.  However, I believe it is the expected behavior.  See this link

http://www.danrigsby.com/blog/index.php/2009/05/20/entity-framework-40-scalar-and-void-functions/

Two things come to mind.

1 you could just get the count property of the entitycollection that is represented by the table context.MyEntitiySet.Count()

2. You could do as the link suggests

ObjectResult<int?> result = context.GetRowCount("MyTableName");
int ret = result.FirstOrDefault().Value.ToString();

Or even shorter

 int ret = context.GetRowCount("MyTableName").FirstOrDefault().Value.ToString();

 

Neither are awesome though

 

 

 

Answer 4

Thank you for the info. context.GetRowCount("MyTableName").First().Value is what I use currently. I don't want to use context.MyEntitiySet.Count(), because it will probably generate a "select count(*)"-type query, which I think can be too expensive with larger tables.