NHibernate HQL – Joining

I think this can be achieved pretty easily if I understand correctly. :) You have a Person object and you want it to contain some properties and a collection of person's addresses that can also be shared amongst other users, right? Well, to set this up using Fluent NHibernate I would do something like this:

// Person Entity
public class Person
{
    public int Id { get; private set; }
    public string Name { get; set; }
    public IList<PersonAddress> Addresses { get; set; }
}

// Fluent Mapping
public class PersonMap : ClassMap<Person>
{
    public PersonMap() {
        Id(x => x.Id);
        Map(x => x.Name);
        HasMany(x => x.Addresses).Cascade.All();
    }
}

// Address Entity
public class Address
{
    public int Id { get; private set; }
    public string Address1 { get; set; }
    public string City { get; set; }
    public IList<PersonAddress> People { get; set; }
}

// Fluent Mapping
public class AddressMap : ClassMap<Address>
{
    public AddressMap() {
        Id(x => x.Id);
        Map(x => x.Address1);
        Map(x => x.City);
        HasMany(x => x.People).Cascade.All();
    }
}

// PersonAddress Entity
public class PersonAddress
{
    public int Id { get; private set; }
    public Person Person { get; set; }
    public Address Address { get; set; }
    public AddressType Type { get; set; }
}

// Fluent Mapping
public class PersonAddressMap : ClassMap<PersonAddress>
{
    public PersonAddressMap() {
        Id(x => x.Id);
        References(x => x.Person);
        References(x => x.Address);
        Map(x => x.Type).CustomTypeIs(typeof(AddressType));
    }
}

Basically, this allows a Person to have a collection of Addresses and those Addresses can be shared amongst the company (multiple persons). You almost have a many-to-many setup but because you storing state info in the PersonAddress it became two one-to-many relationships in the Person and Address Entity.

Sorry if I gave you more than you wanted! Just felt like typing! :p

Let me know if this helps or if you have any questions or if I'm totally off base.

i've found that unusual queries containing left outer joins are better off by using an ISQLQuery which gives you access to proper SQL syntax as well as some HQL power.

Besides that, you don't provide mapping files which usually are helpful