Re: NSFetchedResultsController from a certain object of a to-many relationship of an entity?
Re: NSFetchedResultsController from a certain object of a to-many relationship of an entity?
- Subject: Re: NSFetchedResultsController from a certain object of a to-many relationship of an entity?
- From: Ignacio Enriquez <email@hidden>
- Date: Sun, 8 Aug 2010 23:48:54 +0900
Keary:
>> I have a recursive structure where there are folders and files.
>> Folders can contain various folders and/or files. (File entity has a
>> boolean "isDirectory" flag)
>>
>> Is easy to show the highest (upper) level data in an UITableView but I
>> am not sure how to implement the UITableView datasource for next
>> levels.
>> (The structure was discussed further here:
>> http://www.cocoabuilder.com/archive/cocoa/291457-coredata-warning-file-children-to-many-relationship-does-not-have-an-inverse.html)
>
> The structure as expressed here is inherently flawed, and will likely break down completely at the third tier depth. You need an intermediary entity that maintains inks between item and enclosing "folder".
Could you point what part is exactly inherently flawed? And if
possible, how can I correct it?
>
>> A simple approach would be to get the objects of the relationship of
>> the object at a particular cell and pass this objects set to the new
>> UITableView as its datasource.
>> But I am not sure this is the best approach, specially when the user
>> goes deeper in a big structure (ie.:go to
>> folder>folder>folder>folder>folder>file) is it?
>> (I fell like it would be loosing some CoreData merits like: batchSize,
>> maybe sorting, etc.)
>
> The only drawback I can see with this approach is memory usage. As long as you maintain the "state" of each level as you drill down, you could instead use an NSFecthedResultsController for each level.
How can I create a NSFecthedResultsController for each level ?
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