If you have something like this:
class User
{
public virtual IList<UserRecord> Records {get;set;}
}
And map that using, for example, a bag:
<class name="User" ...>
...
<bag name="Records">
<key column="userid">
<one-to-many class="UserRecord"/>
</bag>
</class>
(you also need to create the mapping for the UserRecord and Record classes,
using <bag> or <set> on the one-to-many side and <many-to-one> on the...
many to one side :-))
Then you can just get the user, and the collection will be loaded for you
(lazily by default, but you can override it):
var user = session.Get<User>(2);
Assert.AreEqual(10, user.Records.Count);
As Fabio said, FORGET about the tables and the SQL. Just design you domain
classes as they are logically related (one user has many records, a record
belongs to a user (many-to-one), etc)
Then you can map that to the existing relational model, or even let
NHibernate generate the model from your mapping.
Diego
On Sun, Nov 29, 2009 at 20:03, Schotime <[email protected]> wrote:
> Ok. I understand, but not sure how to proceed.
>
> I have a User class, Record class and UserRecord class.
>
> Should there be a property on the User class called UserRecords then
> that would have a property on it called Record and get back to the
> data in reverse?
> Any help would be greatly appreciated.
>
> Just trying to get use to it after being so use to querying sql.
>
> Cheers.
> Adam
>
>
> On Nov 29, 10:52 pm, Fabio Maulo <[email protected]> wrote:
> > classes, domain objects, entities... No Table please.
> > You can query it without use the "with" clause.
> >
> > Think on your domain at first, not in its persistent representation.
> >
> > 2009/11/28 Schotime <[email protected]>
> >
> >
> >
> > > hey,
> >
> > > i have two tables. one called records and one called userrecords.
> > > records has the relationship that a record contains multiple
> > > userrecords.
> >
> > > table records:
> > > recordid int identity,
> > > details varchar
> >
> > > table userrecords
> > > userrecordid int identity,
> > > recordid int,
> > > userid int,
> > > extradetails varchar
> >
> > > Will explain with an example.
> > > if there are 10 records and 10 users then you can expect to see 100
> > > user records. One for each combination. A unique index exists on the
> > > userrecords table constraining this.
> >
> > > So if you were to right the query in sql it would be..assuming you are
> > > after the records and user records for user 2.
> >
> > > select * from records r
> > > left outer join userrecords ur on r.recordid = ur.recordid and
> > > ur.userid = 2
> >
> > > this will join the tables correctly so that it will still give you one
> > > user record for each record. If you included the userid as a filter
> > > and there was only 5 user records for user 2 then you would only get 5
> > > rows returned and this would not be correct.
> >
> > > Therefore i tried to right this in hql.
> >
> > > from records r
> > > left join fetch r.userrecords with r.userid = :userid
> >
> > > However I was given the error.
> >
> > > Semantic exception in sqlhqlwalker.cs "with-clause not allowed on
> > > fetched associations; use filters"
> >
> > > If i remove the fetch the query works but then the lazy queries don't
> > > include the userid so the data returned is incorrect.
> >
> > > I'm only new to nhibernate but consider myself fairly competent with
> > > sql. So if there is a better way to structure my model etc, or I
> > > should be doing it another way then I'm open to suggestions too. If
> > > you need more info let me know.
> >
> > > Many thanks,
> > > Adam
> >
> > > --
> >
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> >
> > --
> > Fabio Maulo
>
> --
>
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