Use dynamic type in Entity Framework 4.1 SqlQuery() method

public static class DynamicMapper
{
    private static Dictionary<string, Type> baseEntityTypesByType = new Dictionary<string, Type>();

    public static System.Collections.IEnumerable DynamicSqlQuery(this Database database, string sql, params object[] parameters)
    {

        Type resultType;

        if (baseEntityTypesByType.TryGetValue(sql, out resultType))
        {
            Console.WriteLine("Inside Got the Type");
            if (parameters != null)
                return database.SqlQuery(resultType, sql, parameters);
            return database.SqlQuery(resultType, sql);
        }

        TypeBuilder builder = DynamicMapper.createTypeBuilder(
                "MyDynamicAssembly", "MyDynamicModule", "MyDynamicType");

        using (System.Data.IDbCommand command = database.Connection.CreateCommand())
        {
            try
            {
                database.Connection.Open();
                command.CommandText = sql;
                command.CommandTimeout = command.Connection.ConnectionTimeout;
                if (parameters != null)
                {
                    foreach (var param in parameters)
                    {
                        command.Parameters.Add(param);
                    }
                }

                using (System.Data.IDataReader reader = command.ExecuteReader())
                {
                    var schema = reader.GetSchemaTable();
                    foreach (System.Data.DataRow row in schema.Rows)
                    {
                        string name = (string)row["ColumnName"];
                        Type type = (Type)row["DataType"];
                        var allowNull = (bool) row["AllowDBNull"];
                        if (allowNull)
                        {
                            type = GetNullableType(type);
                        }
                        DynamicMapper.createAutoImplementedProperty(builder, name, type);
                    }
                }
            }
            finally
            {
                database.Connection.Close();
                command.Parameters.Clear();
            }
        }

        resultType = builder.CreateType();
        baseEntityTypesByType[sql] = resultType;

        if (parameters!=null)
        return database.SqlQuery(resultType, sql, parameters);

        return database.SqlQuery(resultType,sql);
    }

    private static TypeBuilder createTypeBuilder(
        string assemblyName, string moduleName, string typeName)
    {
        TypeBuilder typeBuilder = AppDomain
            .CurrentDomain
            .DefineDynamicAssembly(new AssemblyName(assemblyName),
                                   AssemblyBuilderAccess.Run)
            .DefineDynamicModule(moduleName)
            .DefineType(typeName, TypeAttributes.Public);
        typeBuilder.DefineDefaultConstructor(MethodAttributes.Public);
        return typeBuilder;
    }

    private static void createAutoImplementedProperty(
        TypeBuilder builder, string propertyName, Type propertyType)
    {
        const string PrivateFieldPrefix = "m_";
        const string GetterPrefix = "get_";
        const string SetterPrefix = "set_";

        // Generate the field.
        FieldBuilder fieldBuilder = builder.DefineField(
            string.Concat(PrivateFieldPrefix, propertyName),
                          propertyType, FieldAttributes.Private);

        // Generate the property
        PropertyBuilder propertyBuilder = builder.DefineProperty(
            propertyName, PropertyAttributes.HasDefault, propertyType, null);

        // Property getter and setter attributes.
        MethodAttributes propertyMethodAttributes =
            MethodAttributes.Public | MethodAttributes.SpecialName |
            MethodAttributes.HideBySig;

        // Define the getter method.
        MethodBuilder getterMethod = builder.DefineMethod(
            string.Concat(GetterPrefix, propertyName),
            propertyMethodAttributes, propertyType, Type.EmptyTypes);

        // Emit the IL code.
        // ldarg.0
        // ldfld,_field
        // ret
        ILGenerator getterILCode = getterMethod.GetILGenerator();
        getterILCode.Emit(OpCodes.Ldarg_0);
        getterILCode.Emit(OpCodes.Ldfld, fieldBuilder);
        getterILCode.Emit(OpCodes.Ret);

        // Define the setter method.
        MethodBuilder setterMethod = builder.DefineMethod(
            string.Concat(SetterPrefix, propertyName),
            propertyMethodAttributes, null, new Type[] { propertyType });

        // Emit the IL code.
        // ldarg.0
        // ldarg.1
        // stfld,_field
        // ret
        ILGenerator setterILCode = setterMethod.GetILGenerator();
        setterILCode.Emit(OpCodes.Ldarg_0);
        setterILCode.Emit(OpCodes.Ldarg_1);
        setterILCode.Emit(OpCodes.Stfld, fieldBuilder);
        setterILCode.Emit(OpCodes.Ret);

        propertyBuilder.SetGetMethod(getterMethod);
        propertyBuilder.SetSetMethod(setterMethod);
    }

    public static Type GetNullableType(Type TypeToConvert)
    {
        // Abort if no type supplied
        if (TypeToConvert == null)
            return null;

        // If the given type is already nullable, just return it
        if (IsTypeNullable(TypeToConvert))
            return TypeToConvert;

        // If the type is a ValueType and is not System.Void, convert it to a Nullable<Type>
        if (TypeToConvert.IsValueType && TypeToConvert != typeof(void))
            return typeof(Nullable<>).MakeGenericType(TypeToConvert);

        // Done - no conversion
        return null;
    }
    public static bool IsTypeNullable(Type TypeToTest)
    {
        // Abort if no type supplied
        if (TypeToTest == null)
            return false;

        // If this is not a value type, it is a reference type, so it is automatically nullable
        //  (NOTE: All forms of Nullable<T> are value types)
        if (!TypeToTest.IsValueType)
            return true;

        // Report whether TypeToTest is a form of the Nullable<> type
        return TypeToTest.IsGenericType && TypeToTest.GetGenericTypeDefinition() == typeof(Nullable<>);
    }

}