FunctionImport in entity framework 4 issue

Question

I'm using entity framework 4.

I have a stored procedure that just updates one value in my table, namely the application state ID. So I created a stored procedure that looks like this:

ALTER PROCEDURE [dbo].[UpdateApplicationState]
(
   @ApplicationID INT,
   @ApplicationStateID INT
)

AS

BEGIN

   UPDATE
      [Application]
   SET
      ApplicationStateID = @ApplicationStateID
   WHERE
      ApplicationID = @ApplicationID;

END

I created a function import called UpdateApplicationState. I had initially set its return type to null, but then it wasn't created in the context. So I changed its return type to int. Now it was created in the context. Is it wise to return something from my stored procedure?

Here is my method in my ApplicationRepository class:

public void UpdateApplicationState(int applicationID, int applicationStateID)
{
   var result = context.UpdateApplicationState(applicationID, applicationStateID);
}

Here is my calling code to this method in my view:

applicationRepository.UpdateApplicationState(id, newApplicationStateID);

When I run it then I get the following error:

The data reader returned by the store data provider does not have enough columns for the query requested.

Any idea/advise on what I can do to get this to work?

Thanks

Answer 1

To get POCO to work with function imports that return null, you can customize the .Context.tt file like this.

Find the "Function Imports" named region (the section that starts with region.Begin("Function Imports"); and ends with region.End();) in the .Context.tt file and replace that whole section with the following:

    region.Begin("Function Imports");

        foreach (EdmFunction edmFunction in container.FunctionImports)
        {
            var parameters = FunctionImportParameter.Create(edmFunction.Parameters, code, ef);
            string paramList = String.Join(", ", parameters.Select(p => p.FunctionParameterType + " " + p.FunctionParameterName).ToArray());
            var isReturnTypeVoid = edmFunction.ReturnParameter == null;
            string returnTypeElement = String.Empty;
            if (!isReturnTypeVoid) 
                returnTypeElement = code.Escape(ef.GetElementType(edmFunction.ReturnParameter.TypeUsage));

#>
<# if (isReturnTypeVoid) { #>
    <#=Accessibility.ForMethod(edmFunction)#> void <#=code.Escape(edmFunction)#>(<#=paramList#>)    
<# } else { #>
    <#=Accessibility.ForMethod(edmFunction)#> ObjectResult<<#=returnTypeElement#>> <#=code.Escape(edmFunction)#>(<#=paramList#>)    
<# } #>
    {
<#
            foreach (var parameter in parameters)
            {
                if (!parameter.NeedsLocalVariable)
                {
                    continue;
                }
#>

        ObjectParameter <#=parameter.LocalVariableName#>;

        if (<#=parameter.IsNullableOfT ? parameter.FunctionParameterName + ".HasValue" : parameter.FunctionParameterName + " != null"#>)
        {
            <#=parameter.LocalVariableName#> = new ObjectParameter("<#=parameter.EsqlParameterName#>", <#=parameter.FunctionParameterName#>);
        }
        else
        {
            <#=parameter.LocalVariableName#> = new ObjectParameter("<#=parameter.EsqlParameterName#>", typeof(<#=parameter.RawClrTypeName#>));
        }
<#
            }
#>
<# if (isReturnTypeVoid) { #>
        base.ExecuteFunction("<#=edmFunction.Name#>"<#=code.StringBefore(", ", String.Join(", ", parameters.Select(p => p.ExecuteParameterName).ToArray()))#>);
<# } else { #>
        return base.ExecuteFunction<<#=returnTypeElement#>>("<#=edmFunction.Name#>"<#=code.StringBefore(", ", String.Join(", ", parameters.Select(p => p.ExecuteParameterName).ToArray()))#>);
<# } #>

    }
<#
        }

        region.End();

What I'm doing here is instead of ignoring all function imports that return null, I'm creating a method that returns null. I hope this is helpful.