Re: Core Data, abstract Entity problem
Re: Core Data, abstract Entity problem
- Subject: Re: Core Data, abstract Entity problem
- From: "I. Savant" <email@hidden>
- Date: Tue, 24 Jun 2008 09:55:12 -0400
> I could need some help with a Core Data related problem I am experiencing, and I am not entirely sure I understand everything Cocoa does behind my back. In more detail :
It'd be best if you'd post specific questions regarding what you
believe and what you're unsure of. This is essential if you wish to
succeed with this advanced Cocoa topic.
> In Interface Builder, I dragged two "Core Data Entity" library objects on my window - one for the TreeNode entity, one for the TreeGroup entity. Again, I did not change anything except for choosing a Master/Detail view and specifying the addition of Add/Remove buttons.
Why do you want views for both the abstract and the concrete? A view
for TreeNode will show all kinds of TreeNode (TreeGroup and anything
else). Is this really what you want?
> Ok, what I expect to see when I run this and click the "Add TreeGroup" button is a TreeGroup object appearing in the TreeGroup table view (this works all right) and SIMULTANOUSLY a TreeNode "object" (I don't know if this is supposed to be an object since the Entity is abstract) in the TreeNode table view. The problem is, the TreeNode object sometimes appears as soon as I press the add button, sometimes I have to enter a view with the mousepointer for it to appear. No need to say that this is very irritating.
Here's where you're mistaken. Only one *instance* is created: A
'TreeGroup' instance (which is a kind of TreeNode). The reason it's
only showing up in one place reliably is because the add: message is
being sent to *one* controller. Your other controller may not have
been informed that it needs to -fetch: to update its contents.
Hopefully that's enough of a push in the right direction for you to
research this more thoroughly ...
--
I.S.
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