Re: Binding tablecolumn to attribute of specific object in to-many relationship?
Re: Binding tablecolumn to attribute of specific object in to-many relationship?
- Subject: Re: Binding tablecolumn to attribute of specific object in to-many relationship?
- From: Sean McBride <email@hidden>
- Date: Wed, 30 Mar 2011 18:02:24 -0400
- Organization: Rogue Research Inc.
On Tue, 29 Mar 2011 18:15:28 -0700, Quincey Morris said:
>On Mar 29, 2011, at 14:57, Sean McBride wrote:
>
>> I've considered adding a optional transient to-one relationship to
>> Department named 'employeeId0' and binding the tablecolumn to
>> departmentsArrayController>arrangedObjects>employeeId0>name, but maybe
>> I'm barking up the wrong tree....
>
>There's no obvious reason from your description why employee ID 0 needs
>to be a Core Data property. Surely it can just be a normal derived property.
>
>Also, if it has no particular significance other than for populating the
>list, there's no real reason to implement the property in the data model
>itself. It seems more natural to implement it in your window controller.
>
>But I don't see anything actually wrong with your original suggestion,
>if you have a compelling reason to go that way.
Quincey,
Thanks for your reply. However, I'm not sure I understand you exactly.
By 'normal derived property' do you mean in this sense:
<http://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/
CoreData/Articles/cdFAQ.html#//apple_ref/doc/uid/TP40001802-SW3>
That FAQ is actually pretty darn close to my original question really.
But it's a little vague. I've never been clear on when/where it's safe
to use KVO from one managedobject to another. It says "You must add and
remove the parent [Department] as an observer as child objects
[Employees] are added to and removed from the relationship". Where's
the correct place to catch items being added to/removed from a
relationship? By implementing addEmployeesObject: and
removeEmployeesObject: in my Department class?
Cheers,
--
____________________________________________________________
Sean McBride, B. Eng email@hidden
Rogue Research www.rogue-research.com
Mac Software Developer Montréal, Québec, Canada
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