Re: How to fetch eo with a specific relationship
Re: How to fetch eo with a specific relationship
- Subject: Re: How to fetch eo with a specific relationship
- From: David Avendasora <email@hidden>
- Date: Wed, 6 Feb 2008 13:56:51 -0500
|
I agree with this completely. WO will load ALL the to-many-related objects from the database when you try to set the inverse to-one relationship on a new object, which when there are thousands of related objects, this can cause a huge delay, especially in Java Client applications where the client then requests all the objects be sent to the client from the server. Ouch.
I have always just not modeled the inverse, unless I discovered a compelling reason to _expect_ all the related objects to be in memory. I didn't realize that if the relationship isn't marked as a class attribute that it wouldn't fetch them. That is interesting and would make the model much more intuitive.
Using a FetchSpec to go get the to-many-related objects manually has worked well for me as it only incurs the often substantial overhead if and when I explicitly ask it to.
Dave
On Feb 6, 2008, at 11:32 AM, Robert Walker wrote: At least if using standard EOF classes, having the reverse to-many relationship as a class properly on the EO can cause very major performance problems because the to-many fault can get fired when you don't expect it. This can happen even if you never directly access the to-many relationship. I've had nightmares about this very problem in the past. I now consider the implication of adding the to-many side as a class property. If I expect it could return more than a few hundred objects then I don't use it. I still model the to-many side, I just don't set it as a class property. It's entirely possible that Project WOnder classes take care of this problem. I just wanted to make sure you were aware of it.
|
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Webobjects-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden