public void Insert(Domain.Models.ProductAggregate.Product entity)
{
Models.Product product = entity.ToRepositoryModel();
// avoids inserting children elements
var productClone = product.DeepClone();
productClone.ProductParts = null;
this.InsertProduct(productClone);
IEnumerable <Models.Material> materials = product.ProductParts
.Select(p => p.ProductPartMaterials.Select(m => m.Material))
.SelectMany(m => m);
this.InsertMaterials(materials);
this.InsertProductParts(product);
}