Hi there,

I have a very complicated object model/database - when I try to load the entity that's at the top of the tree (using session.load) I can see 4000+ lines of sql being generated. I have tried to tune this using fetch="join" on the main offending collection - this attempts to join but the query is then too complex.

When I set this back to "select" mode however, then change some of the descendant collections to use fetch="join", this seems to be ignored. I have tried to be more fine grained using the criteria objects and setting the FetchMode, more or less as follows:




... but because I'm using 'createcriteria' on the first collection it automatically tries to use a join (I have also tried specifying the JoinType.None).... ChildCollection2 is mapped using fetch="join" but as described in the 1st scenario, this seems to be ignored...

Can anybody help please?

Thanks in anticipation, Carl

Please,

Can you send us your mapping file?

Tks

Hi luiz,

I can't send you the entire thing I'm afraid but here's the mapped collection on the first parent object:



And this is a collection on a 'Stage':



essentially I want the stages to be retrieved with a select, but the assumptions under that stage to be retrieved with a join....

Thanks, Carl

Hi CarlHowarth,

I think your problem is due the lazy property.
Change the value of this property to TRUE (lazy="true").

When you execute a query, this property won't bring all these record once.

Hope it's help

Hi again - thanks, but the problem is more that I can get my first collection to load using a select, but I want the child collections to load using a join, and that's where the trouble lies.

Hi! I don't know how to this with Criterias, but in HQL there is a key fetch

so try this query

select p from Parent p
join fetch p.ChildCollection c
where p.ParentID=12345

see the fetch argument? it will enable to load all entities along from childcollection without making n+1

recommend you to read a http://nhforge.org blog posts