private static void ProcessLenses(IEnumerable<XElement> lenses, Manufacturer manu, PhotographySystemEntities context)
        {
            foreach (var lens in lenses)
            {

                var lensModel = lens.Attribute("model").Value;
                var lensType = lens.Attribute("type").Value;
                var xlensPrice = lens.Attribute("price");
                string lensPrice = null;
                if (xlensPrice != null)
                {
                    lensPrice = xlensPrice.Value;
                }
                var newLens = context.Lenses.FirstOrDefault(l => l.Model == lensModel);
                if (newLens == null)
                {
                    newLens = new Lens {Model = lensModel, Type = lensType};
                    if (lensPrice != null)
                    {
                        newLens.Price = decimal.Parse(lensPrice);
                    }
                    context.Lenses.Add(newLens);
                    manu.Lenses.Add(newLens);
                    context.SaveChanges();
                    Console.WriteLine("Created lens: {0}", lensModel);
                }
                else
                {
                    Console.WriteLine("Existing lens: {0}", lensModel);
                }
            }
        }
 private static Manufacturer ProcessManufacturer(XElement manufacturer, PhotographySystemEntities context)
 {
     var manuName = manufacturer.Element("manufacturer-name").Value;
     var manu = context.Manufacturers.FirstOrDefault(m => m.Name == manuName);
     if (manu == null)
     {
         manu = new Manufacturer {Name = manuName};
         context.Manufacturers.Add(manu);
         context.SaveChanges();
         Console.WriteLine("Created manufacturer: {0}", manuName);
     }
     else
     {
         Console.WriteLine("Existing manufacturer: {0}", manuName);
     }
     return manu;
 }