Best way to filter collection

jeaf · **Joined:** Thu Aug 27, 2009 5:08 am **Posts:** 3

Hi
I have the following scenario.

I have a list of Customers, each customer has a list of Orders. I want to get all the customers but i only want to load the orders for the customers within a specific date range. Whats the best way to solve this with ICriteria? Should I use CreateFilter on the session insted?

Is it in some way possible to create this filtering already in the ICriteria?

/Edit
I dont want to use filter, because it will produce to many selects. Is it possible with ICriteria thou?

Regards

jonegomes · **Joined:** Tue Dec 22, 2009 9:39 am **Posts:** 3

Are you sure you want to filter the Collection itself, rather than an iterator? see org.apache.commons.collections.iterators.FilterIterator

anlugifa · **Joined:** Sat Jan 09, 2010 3:23 pm **Posts:** 5

Code:

session.CreateCriteria(typeof(Order))
                        .Add(Expression.Between("Date", date_min, date_max))
                        .List()

Cheers,
Andre

nadavsof · **Joined:** Sat Dec 26, 2009 7:05 am **Posts:** 8

you can do this with one db acces :

create a criteria on customers : custCriteria
custCriteria.CreateCriteria("Orders","Order", NHibernate.SqlCommand.JoinType.LeftOuterJoin)
now add a criterion as the user above me showed, but with the alias Order
this will fetch all employees (because it is a left out join) and only the wanted orders
or you could do as he said with 2 db access. the more efficient strategy depends mainly on how big is the customer record (with a join, the same customer record returns few times - one for each of its orders)

also, if you use a join, use result transformer to return any root entity only once