how can I change a sql query to linq 2 nhibernate? - sql-server-2005

Question

I have a query that is driving me crazy,,when I run it in sql it works fine but I dont know how to change it to linq to sql
the query is:
SELECT organizationstructure.PositionTitle.Title, organizationstructure.Person.FirstName, organizationstructure.Person.LastName,
organizationstructure.Department.Name
FROM organizationstructure.Department INNER JOIN
organizationstructure.Accountability AS Accountability_1 ON organizationstructure.Department.PartyId = Accountability_1.ParentPartyId INNER JOIN
organizationstructure.Accountability INNER JOIN
organizationstructure.Person ON organizationstructure.Accountability.ChildPartyId = organizationstructure.Person.PartyId INNER JOIN
organizationstructure.Position ON organizationstructure.Accountability.ParentPartyId = organizationstructure.Position.PartyId ON
Accountability_1.ChildPartyId = organizationstructure.Position.PartyId INNER JOIN
organizationstructure.PositionTitle ON organizationstructure.Position.PositionTitleId = organizationstructure.PositionTitle.PositionTitleId
and I think this is wrong but I changed it to:
query// query is iqueryable of position
.Join(Repository<Accountability>.Find(), p => p.Id, a => a.Child.Id,
(p, a) => new Tuple<string, string, int?>(((Department)a.Parent).Name, p.PositionTitle.Title, p.Id))
.Join(Repository<Accountability>.Find(), p => p.Item3, p => p.Parent.Id,
(p, d) => new Tuple<string, string, int?, string>(p.Item1, p.Item2, p.Item3, d.Child == null ? string.Empty : string.Format("{0}", ((Person)d.Child).FirstName) + " " + ((Person)d.Child).LastName))
whats wrong with it or ow can i change this query??

Answer 1

Generally having to do excessive numbers of explicit joins in your linq to nhibernate is a sign that you've not mapped your database to your domain appropriately. Without mappings between objects then you will just be reproducing SQL in your linq, which is a bit of a waste of time.
Your mappings should specify the relationships between the objects in your domain - for instance, a "Person" might have a reference to a "PositionTitle". If you use the mappings to setup relationships in this way then your query could end up looking something like this:
var results =
from
p in mySession.Query<Person>
select
new PersonalDetails
{
Title = p.PositionTitle.Title,
FirstName = p.FirstName,
LastName = p.LastName
DepartmentName = p.Party.Department.Name
};