Re: How troubleshoot when Managed Object disappears from Store?
Re: How troubleshoot when Managed Object disappears from Store?
- Subject: Re: How troubleshoot when Managed Object disappears from Store?
- From: Quincey Morris <email@hidden>
- Date: Sun, 1 Aug 2010 20:59:09 -0700
On Aug 1, 2010, at 18:31, Jerry Krinock wrote:
> When initializing an NSPersistentDocument with sqlite store in a Mac app, I insert what I call a "singleton" managed object, like the "Department" in DepartmentAndEmployees. It's simply a container which has a to-many relationship to its containees (i.e., employees). Delete Rule is Nullify.
>
> I've reproduced a bug whereupon, during some seemingly unrelated Core Data operations, this singleton object, which was in the store initially, is gone. I know this from saving the document, and then dumping the document file using sqlite3. The related CREATE TABLE and CREATE INDEX statements are still there, but the singular INSERT INTO statement is gone.
>
> I tried to break in the debugger when the object disappears, by overriding -willTurnIntoFault, -didTurnIntoFault, and -validateForDelete:, but none of these messages are received.
>
> Sometimes other objects disappear too, and it's possible that the store is being "hosed" more generally. But, oddly, I don't get even a peep from Core Data in console. It even loads OK if I close and reopen the document.
Are you sure this isn't just a memory management error, perhaps in combination with an incorrect delete rule? What's the delete rule for the "department" relationship in the "Employee" entity? Is there a strong reference that keeps the singleton "Department" alive even when there's no fetched "Employee" or unfaulted "Employee" in memory?
If the disappearance is a result of the singleton being disposed of (for whatever reason), would Instruments' Object Allocations tell you anything about why or when or where the singleton died?
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