For a simple example, let's say you have a Department table, which has some other object references (perhaps to a DepartmentType table and some other stuff). This table also has a self reference (nullable) to another Department, which is its parent department. The class also has a "children" bag called SubDepartments, which is set to lazy load.

I have this working fine as a many-to-one relationship from the class to itself through a column named parent_id. My question is, how can you make this a lazy loading relationship, so that you don't get back this huge graph of parents/children by loading a deeply nested department?

As I recall, Hibernate supports lazy="true" on many-to-one relationships, but this doesn't work in NHibernate. Is this something I should worry about, or am I missing something?

I can provide a mapping and schema example if necessary. Thanks!

That's outdated information, NHibernate supports lazy-loading of <many-to-one> since 0.6 or so.

IIRC, lazy="true" on <many-to-one> (and <one-to-many>) relationships work in NHibernate (0.8.2.0).


Cf. http://sourceforge.net/project/shownote ... _id=326230

And "Proxy" is the way to lazy load <many-to-one>.

Hmm, I must have misidentified an error then (i.e., I may have had some other problem with the mapping file and wrongly attributed it to the lazy property). Thanks, I will definitely try this again when I get home!

In 1.0.2, if I try to put a lazy="true" attribute on a <many-to-one ...> declaration, I get an error "The 'lazy' attribute is not declared". Am I missing something?

Thank you!
-Michael

lazy="true" is intended to be used in <class>, not in <many-to-one>.

So what does that actually mean? Any reference to that class by another class would automatically be lazy-loaded?

-MT

Yes.