Error message with Entity Framework and Function Import

Question

I have a DB stored procedure that returns a float. The Stored proc does calculations of inputs and spits out a "Rating" based in the inputs. I was able to update the Model and perform a function import, but when I try and use the new function in Linq i get the following error.

Function metadata used in DbFunctionExpression must allow composition. Non-composable functions or functions that include command text are not allowed in expressions.

I have no idea what that means, and a Google search returned nothing.

Relevant code follows:

public static class EntityFunctions
{
    [EdmFunction("RateMyNeighborhoodModel.Store","RMNIndex")]
    public static decimal? RMNIndex
       (
       float Unemployment,
       float AverageCommuteTime,
       float FamiliesBelowPoverty,
       float TotalCrime,
       float PersonalCrime,
       float Murder,
       float Rape,
       float Robbery,
       float Assault,
       float PropertyCrime,
       float Burgulary,
       float Larceny,
       float VehicleTheft,
       float SexOffenderCount
       )
    {
        throw new NotSupportedException();
    }

}


 var neighborhoodViews = (from 
                                     nv in db.NeighborhoodViews 
                                 join
                                     n in db.Neighborhoods.Include("ZipCodeStatistic") on nv.NeighborhoodID equals n.NeighborhoodID
                                 where
                                     EntityFunctions.RMNIndex((float)n.UnemploymentRate, (float)nv.AverageCommuteTime, (float)nv.familiesBelowPoverty, (float)nv.TotalCrime, (float)nv.PersonalCrime, (float)nv.Murder, (float)nv.Rape, (float)nv.Robbery, (float)nv.Assault, (float)nv.PropertyCrime, (float)nv.Burgulary, (float)nv.Larceny, (float)nv.VehicleTheft, (float)n.ZipCodeStatistic.SexOffenders) > 4 
                                 orderby 
                                    Guid.NewGuid() 
                                 select new 
                                 {
                                     City = n.City,
                                     GeographyData = nv.Geography,
                                     ID = n.NeighborhoodID,
                                     Latitude = Single.Parse(nv.Center.Replace("POINT (", "").Replace(")", "").Split(' ')[1]),
                                     Longitude = Single.Parse(nv.Center.Replace("POINT (", "").Replace(")", "").Split(' ')[0]),
                                     Name = n.Name,
                                     State = n.State,
                                     UpdateDate = n.UpdateDate,
                                     RMNIndex = EntityFunctions.RMNIndex((float)n.UnemploymentRate, (float)nv.AverageCommuteTime, (float)nv.familiesBelowPoverty, (float)nv.TotalCrime, (float)nv.PersonalCrime, (float)nv.Murder, (float)nv.Rape, (float)nv.Robbery, (float)nv.Assault, (float)nv.PropertyCrime, (float)nv.Burgulary, (float)nv.Larceny, (float)nv.VehicleTheft, (float)n.ZipCodeStatistic.SexOffenders),
                                     Zipcode = n.ZipCodeStatistic.ZipCode,
                                     TotalCrime = (double)n.ZipCodeStatistic.TotalCrime,
                                     PersonalCrime = (double)n.ZipCodeStatistic.PersonalCrime,
                                     Murder = (double)n.ZipCodeStatistic.Murder,
                                     Rape = (double)n.ZipCodeStatistic.Rape,
                                     Robbery = (double)n.ZipCodeStatistic.Robbery,
                                     Assault = (double)n.ZipCodeStatistic.Assault,
                                     PropertyCrime = (double)n.ZipCodeStatistic.PropertyCrime,
                                     Burgulary = (double)n.ZipCodeStatistic.Burgulary,
                                     Larceny = (double)n.ZipCodeStatistic.Larceny,
                                     VehicleTheft = (double)n.ZipCodeStatistic.VehicleTheft,
                                     AverageCommuteTime = (double)n.ZipCodeStatistic.AverageCommuteTime,
                                     UnemploymentRate = (double)n.ZipCodeStatistic.UnemploymentRate,
                                     FamiliesBelowPoverty = (double)nv.familiesBelowPoverty,
                                     SexOffenderCount = (int)n.ZipCodeStatistic.SexOffenders

                                 }).Take(5);

Answer 1

The problem was that I was using a Stored Procedure and a function import. When i converted the stored procedure to a scalar function I was able to use it the way I had intended.