EF4 - The selected stored procedure returns no columns

Question

I have query in a stored procedure that calls some linked servers with some dynamic SQL. I understand that EF doesn't like that, so I specifically listed all the columns that would be returned. Yet, it still doesn't like that. What am I doing wrong here? I just want EF to be able to detect the columns returned from the stored procedure so I can create the classes I need.

Please see the following code that makes up the last lines of my stored procedure:

SELECT
    #TempMain.ID,
    #TempMain.Class_Data,
    #TempMain.Web_Store_Class1,
    #TempMain.Web_Store_Class2,
    #TempMain.Web_Store_Status,
    #TempMain.Cur_1pc_Cat51_Price,
    #TempMain.Cur_1pc_Cat52_Price,
    #TempMain.Cur_1pc_Cat61_Price,
    #TempMain.Cur_1pc_Cat62_Price,
    #TempMain.Cur_1pc_Cat63_Price,
    #TempMain.Flat_Length,
    #TempMain.Flat_Width,
    #TempMain.Item_Height,
    #TempMain.Item_Weight,
    #TempMain.Um,
    #TempMain.Lead_Time_Code,
    #TempMain.Wp_Image_Nme,
    #TempMain.Wp_Mod_Dte,
    #TempMain.Catalog_Price_Chg_Dt,
    #TempMain.Description,
    #TempMain.Supersede_Ctl,
    #TempMain.Supersede_Pn,
    TempDesc.Cust_Desc,
    TempMfgr.Mfgr_Item_Nbr,
    TempMfgr.Mfgr_Name,
    TempMfgr.Vendor_ID
FROM
    #TempMain
        LEFT JOIN TempDesc ON #TempMain.ID = TempDesc.ID
        LEFT JOIN TempMfgr ON #TempMain.ID = TempMfgr.ID

Answer 1

EF doesn't support importing stored procedures which build result set from:

• Dynamic queries
• Temporary tables

The reason is that to import the procedure EF must execute it. Such operation can be dangerous because it can trigger some changes in the database. Because of that EF uses special SQL command before it executes the stored procedure:

SET FMTONLY ON

By executing this command stored procedure will return only "metadata" about columns in its result set and it will not execute its logic. But because the logic wasn't executed there is no temporary table (or built dynamic query) so metadata contains nothing.

You have two choices (except the one which requires re-writing your stored procedure to not use these features):

• Define the returned complex type manually (I guess it should work)
• Use a hack and just for adding the stored procedure put at its beginning SET FMTONLY OFF. This will allow rest of your SP's code to execute in normal way. Just make sure that your SP doesn't modify any data because these modifications will be executed during import! After successful import remove that hack.

Answer 2

Adding this Non-Logical block of code solved the problem. Even though it will never Hit

IF 1=0 BEGIN
    SET FMTONLY OFF
END

Why does my typed dataset not like temporary tables?

http://social.msdn.microsoft.com/Forums/en-US/adodotnetdataset/thread/fe76d511-64a8-436d-9c16-6d09ecf436ea/

Answer 3

Or you can create a User-Defined Table Type and return that.

CREATE TYPE T1 AS TABLE 
( ID bigint NOT NULL
  ,Field1 varchar(max) COLLATE Latin1_General_CI_AI NOT NULL
  ,Field2 bit NOT NULL
  ,Field3 varchar(500) NOT NULL
  );
GO

Then in the procedure:

DECLARE @tempTable dbo.T1

INSERT @tempTable (ID, Field1, Field2, Field3)
SELECT .....

....

SELECT * FROM @tempTable

Now EF should be able to recognize the returned columns type.

Answer 4

As some others have noted, make sure the procedure actually runs. In particular, in my case, I was running the procedure happily without error in SQL Server Management Studio completely forgetting that I was logged in with admin rights. As soon as I tried running the procedure using my application's principal user I found there was a table in the query that that user did not have permission to access.

Answer 5

Interesting side note: Had the same problem which I first solved by using Table Variables, rather than Temp Tables (just for the import). That wasn't particularly intuitive to me, and threw me off when initially observing my two SProcs: one using Temp tables and one with Table Variables.

(SET FMTONLY OFF never worked for me, so I just changed my SProcs temporarily to get the column info, rather than bothering with the hack on the EF side just as an FYI.)

My best option was really just manually creating the complex type and mapping the function import to it. Worked great, and the only difference ended up being that an additional FactoryMethod to create the properties was included in the Designer.

Answer 6

What I would add is:

That the import also fails if the stored procedures has parameters and returns no result set for the default parameter values.

My stored procedure had 2 float parameters and would not return anything when both parameters are 0.

So in order to add this stored procedure to the entity model, I set the value of these parameters in the stored procedure so that it is guaranteed to return some rows, no matter what the parameters actually are.

Then after adding this stored procedure to the entity model I undid the changes.

Answer 7

both solutions : 1- Define the returned complex type manually (I guess it should work) 2- Use a hack and just for adding the stored procedure put at its beginning SET FMTONLY OFF.

not working with me in some procedure however it worked with other one!

my procedure ends with this line:

SELECT machineId, production [AProduction]
        , (select production FROM #ShiftBFinalProd WHERE machineId = #ShiftAFinalProd.machineId) [BProduction]
        , (select production FROM #ShiftCFinalProd WHERE machineId = #ShiftAFinalProd.machineId) [CProduction]
     FROM #ShiftAFinalProd
     ORDER BY machineId

Thanks

Answer 8

In addition to what @tmanthley said, be sure that your stored procedure actually works by running it first in SSMS. I had imported some stored procedures and forgot about a couple dependent scalar functions, which caused EF to determine that the procedure returned no columns. Seems like a mistake I should have caught earlier on, but EF doesn't give you an error message in that case.

Answer 9

Entity Framework will try to get the columns by executing your stored procedure, passing NULL for every argument.

1. Please make sure that the stored procedure will return something under all the circumstances. Note it may have been smarter for Entity Framework to execute the stored proc with default values for the arguments, as opposed to NULLs.

2. ER does the following to get the metadata of the table:

   SET FMTONLY ON

3. This will break your stored procedure in various circumstances, in particular, if it uses a temporary table.

4. So to get a result as complex type; please try by adding

   SET FMTONLY OFF;

This worked for me - hope it works for you too.

Referred from https://social.msdn.microsoft.com/Forums/en-US/e7f598a2-6827-4b27-a09d-aefe733b48e6/entity-model-add-function-import-stored-procedure-returns-no-columns?forum=adodotnetentityframework

Answer 10

In my case adding SET NOCOUNT ON; at the top of the procedure fixed the problem. It's best practice anyway.

Answer 11

In my case SET FMTONLY OFF did not work. The method I followed is, I took backup of original stored procedure and replace with only column name like the below query.

Select Convert(max,'') as Id,Convert(max,'') as Name

After this change, create new function import, complex type in entity framework. Once the function import and complex type is created, replace the above query with your original stored procedure.

Answer 12

SET FMTONLY OFF 

worked for me for one of the procedure but failed for other procedure. Following steps helps me to resolve my problem

1. Within a stored procedure, I have created temporary table with the same column type and inserted all the data returned by dynamic query to temp table. and selected the temp table data.

   Create table #temp
   (
      -- columns with same types as dynamic query    
   )
   
   EXEC sp_executeSQL @sql 
   
   insert into #temp 
       Select * from #temp 
   
   drop table #temp
   

2. Deleted existing complex type, import function and stored procedure instance for old stored procedure and updated entity model for current new procedure.

3. Edit the imported Function in entity modal for desired complex type, you will get all the column information there which is not getting for previous stored procedure.

4. once you have done with the type creation you can delete the temporary table from stored procedure and then refresh Entity Framework.

Answer 13

In Entity framework, while getting column information the sql executes the procedure with passing null values in parameter. So I handled null case differently by creating a temp table with all the required columns and returning all the columns with no value when null is passed to the procedure.

In my procedure there was dynamic query, something like

declare @category_id    int
set @category_id = (SELECT CATEGORY_ID FROM CORE_USER where USER_ID = @USER_ID)
declare @tableName varchar(15)
declare @sql VARCHAR(max)     
declare  @USER_IDT  varchar(100)    
declare @SESSION_IDT  varchar(10)

 IF (@category_id = 3)     
set @tableName =  'STUD_STUDENT'
else if(@category_id = 4)
set @tableName = 'STUD_GUARDIAN'


if isnull(@tableName,'')<>'' 
begin

set @sql  = 'SELECT  [USER_ID], [FIRST_NAME], SCHOOL_NAME, SOCIETY_NAME, SCHOOL_ID,
SESSION_ID, [START_DATE], [END_DATE]
from  @tableName
....
EXECUTE   (@sql)
END

ELSE
BEGIN
SELECT  * from #UserPrfTemp
END

I was not getting the column information in my case after using the set FMTONLY OFF trick.

This is temp table I created to get the blank data. Now I am getting the column info

Create table #UserPrfTemp
(
[USER_ID] bigint, 
[FIRST_NAME] nvarchar(60),
SCHOOL_NAME nvarchar(60),
SOCIETY_NAME nvarchar(200)
.....
}

Answer 14

I solved this problem creating a table variable and then returning from it.

DECLARE @VarTable TABLE (
    NeededColumn1                       VARCHAR(100),
    NeededColumn2                       INT,
    NeededColumn3                       VARCHAR(100)
)

...

--Fetch Data from Linked server here

...

INSERT INTO @VarTable (NeededColumn1,NeededColumn2,NeededColumn3)
SELECT Column1, Column2, Column3
FROM #TempTable

SELECT * FROM @VarTable.

In that manner, your the SP result will be bounded to the table variable, which EF has access to.

Answer 15

I discovered a method that should help most people out whatever's happening.

Pull up your favourite SQL client and run the proc that you're trying to update with every parameter = null. Visual Studio is literally trying to do this when SET FMTONLY ON. Run a trace. You'll see.

You'll probably get an error, or unexpected data out. Fix that and your issue is fixed.

In my case the function read in JSON and failed because the JSON string was empty.

I just put something like

IF(@FooJSON IS NULL)
BEGIN
  SELECT 1 VAR1, 2 VAR2;
END
ELSE
--OTHER LOGIC

That's probably an ugly solution, but I inherited this mess and we don't go into Ravenholm.

Answer 16

Change #Temp tables with WITH SQL EXPRESSION