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PONeed some help understanding faulting in Core Data
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copied!<p>I have a Core Data entity that uses a custom subclass of NSManagedObject. I have a few instance variables and properties on it that aren't associated with Core Data attributes or relationships. An example of the kind of thing I'm doing is this:</p> <pre><code>@interface Root : NSManagedObject { Foo *foo; Bar *bar; } @property (nonatomic, retain) Foo *foo; @property (nonatomic, retain) Bar *bar; // Core Data generated @property (nonatomic, retain) Node *relationship; @property (nonatomic, retain) NSString *attribute; -(void)awake; @end @implementation Root @synthesize foo; @synthesize bar; @dynamic relationship; @dynamic attribute; -(void)awakeFromInsert { [super awakeFromInsert]; [self awake]; } -(void)awakeFromFetch { [super awakeFromFetch]; [self awake]; } -(void)awake { Foo *newFoo = [[Foo alloc] init]; self.foo = newFoo; [newFoo release]; // bar is not automatically initialized, but can be set by something external } -(void)didTurnIntoFault { [foo release]; foo = nil; [bar release]; bar = nil; [super didTurnIntoFault]; } @end </code></pre> <p>Now in my app I get an instance of Root by a fetch request once when the app launches, and I retain it until the app quits. (Actually it's a bit more complicated because you can delete the root instance and create a new one, but at most one exists at a time and it is retained.) So my hope is that didTurnIntoFault will never be called until my app quits. If it did, then at some point I would refer to root.foo or root.bar and get nil. That would be an error for my app. A Root instance should always have a non-nil value for foo and bar; foo is created whenever the instance is loaded, and bar is set by the caller immediately after fetching the root instance.</p> <p>Can I rely on didTurnIntoFault not being called, if my code is retaining the NSManagedObject?</p> <p>If I don't want didTurnInfoFault to be called, why do I have it? Well, I have to clean up sometime. Maybe I should really put that code into dealloc, if I don't want those instance variables released until the program quits. But I think I read some documentation that discouraged using dealloc for subclasses of NSManagedObject.</p>

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