Hi guys

I have an object with many-to-one relation to other objects. In my web apps I display a list of items . But only few member of the object, need to be display. Like the name the email etc.

The problem that I have is that my apps is not performant. After reading trought the log I think that the cause of the problem is that all the object are load and then it resolves all the relation that are man-to-one.

So my question is how can I load the properties only when i need them. Likje the lazyload for the collections ( ah btw my collections are lazy load so at least thay are not load with all other relations...)


any ideas?


here is a part of the log

[code]

2005-10-27 15:40:01,872 [2456] DEBUG NHibernate.Type.NullableType [(null)] <(null)> - returning '452' as column: IdService
2005-10-27 15:40:01,872 [2456] DEBUG NHibernate.Loader.Loader [(null)] <(null)> - result row: 452
2005-10-27 15:40:01,872 [2456] DEBUG NHibernate.Loader.Loader [(null)] <(null)> - Initializing object from DataReader: 452
2005-10-27 15:40:01,872 [2456] DEBUG NHibernate.Loader.Loader [(null)] <(null)> - Hydrating entity: Datablitz.Engine.objets.ServiceEmissionRadio#452
2005-10-27 15:40:01,872 [2456] DEBUG NHibernate.Type.NullableType [(null)] <(null)> - returning null as column: HeureDebut
2005-10-27 15:40:01,872 [2456] DEBUG NHibernate.Type.NullableType [(null)] <(null)> - returning null as column: SiteWeb
2005-10-27 15:40:01,872 [2456] DEBUG NHibernate.Type.NullableType [(null)] <(null)> - returning '10' as column: IdMedia
2005-10-27 15:40:01,872 [2456] DEBUG NHibernate.Type.NullableType [(null)] <(null)> - returning 'Diff

Ok I found this article. It talk exactly about the problem that I have. I will need to implement what he call the advanced soltution. Anyone know if its possible to do something like that with NHibernate 1.0 ?

http://www.jroller.com/page/wakaleo/?anchor=hibernate_optimisation

Hrm, I thought the thing to do to get lazy loading of many-to-one properties was to use proxies in the mapping? I haven't experimented with that yet, but it seems like a lot cleaner solution that what that article suggested.

Unfortunately NHibernate 1.0 is a port of Hibernate 2 which doesn't support lazy loading of specific properties which means you'd need ot use a data transfer object as described earlier in the post you referred to.

Cheers,

Symon.

Thanks for your reply guys! I used the "select new" clause and it drasticly improve the performance of my apps. I created an object with only the properties that i needed.. but yes it would have been much more cleaner if i could used the method explained in the aricle. btw I though that NHibernate 1,0 was a port of Hibernate 2.1 and the article seems to use Hibernate 2.1 thats why i asked if it was possible to replicate the solution with NHibernate.

Simon

Hi Simon,

Hmm...Looks like you and I are working on the same sort of thing at the same time. I've just posted a request for info on using 'select new' because I can't get it to work. I always get a 'class not found' exception for the data transfer class.

Any hints?

Cheers,

Symon.