What libraries do i use for compiling a linq to entities query

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using ///what here



public static class CompiledQueries 
{ 
    public static Func<DataContext, int, IQueryable<Foo>> getFoo = 
        CompiledQuery.Compile(
        (DataContext db, int ixFoo) => 
            (from f in db.Foo where f.ix == ixFoo sele开发者_如何学JAVAct f));
}

any ideas

add reference to System.Data.Entity

using System.Data.Objects