Suppose I have
public class Product: Entity
{
public IList<Item> Items { get; set; }
}
Suppose I want to find an item with max something... I can add the method Product.GetMaxItemSmth() and do it with Linq (from i in Items select i.smth).Max()) or with a manual loop or whatever. Now, the problem is that this will load the full collection into memory.
The correct solution will be to do a specific DB query, but domain entities do not have access to repositories, right? So either I do
productRepository.GetMaxItemSmth(product)
(which is ugly, no?), or even if entities have access to repositories, I use IProductRepository from entity
product.GetMaxItemSmth() { return Service.GetRepository<IProductRepository>().GetMaxItemSmth(); }
which is also ugly and is a duplication of code. I can even go fancy and do an extension
public static IList<Item> GetMaxItemSmth(this Product product)
{
return Service.GetRepository<IProductRepository>().GetMaxItemSmth();
}
which is better only because it doesn't really clutter the entity with repository... but still does method duplication.
Now, this is the problem of whether to use product.GetMaxItemSmth() or productRepository.GetMaxItemSmth(product)... again. Did I miss something in DDD? What is the correct way here? Just use productRepository.GetMaxItemSmth(product)? Is this what everyone uses and are happy with?
I just don't feel it is right... if I can't access a product's Items from the product itself, why do I need this collection in Product at all??? And then, can Product do anything useful if it can't use specific queries and access its collections without performance hits?
Of course, I can use a less efficient way and n