[elephant-devel] Re: Master-detail how to

[Vagif Verdi]

If I will make item class persistent, then items will be saved independently
of their parent. That means manual housekeeping.
When order object is deleted, I will have to intercept that and manually
delete all items objects.
And this is only simplest hierarchy. 
Imagine how much manual work must be done in case or deeper hierarchies.

Maybe I do not understand how elephant work.
Maybe it somehow automatically deletes all objects that are in a pset slot
of the object being deleted.
Is that the case?


-----Original Message-----
From: elephant-devel-bounces at common-lisp.net
[mailto:elephant-devel-bounces at common-lisp.net] On Behalf Of Alex Mizrahi
Sent: Sunday, April 06, 2008 4:38 AM
To: elephant-devel at common-lisp.net
Subject: [elephant-devel] Re: Master-detail how to

 VV> Obviously class order must be persistent. But what about class
 VV> order-item? Should it be persistent too?

it's better to make it persistent, so you can search on details.

 VV> Next question. How do you search orders that have say particular item?

(mapcar #'order-of (get-instances-by-value 'order-item 'item item))

 VV> Do you create a computed index on order class?

some complex queries require computed indices, but it seems not in this case

 VV>  Or do you make item class persistent and mark its name as indexed?

if you're using objects anyway it makes sense to make everything a 
persistent object 



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