Re: a HUGE Core Data bug
Re: a HUGE Core Data bug
- Subject: Re: a HUGE Core Data bug
- From: email@hidden
- Date: Fri, 09 Mar 2007 19:52:03 +0100
So in the end it's not a bug but a feature? ;-)
In this case the answer seems to be: Yes! In the ADC-Document "Core Data
Programming Guide" you'll find this statement in the section
"Relationships":
"... Not modeling a relationship in both directions, however, imposes on
you a great number of responsibilities, to ensure the consistency of the
object graph, for change tracking, and for undo management. For this
reason, the practice is strongly discouraged. It typically only makes
sense to model a to-one relationship in one direction."
Does your example probably miss something thats necessary to ensure the
models consistency?
Wolfgang
I. Savant schrieb:
Aurélien:
To say, "... but honestly I can't trust Core Data anymore ..." is a
bit alarmist, don't you think?
Should this be happening? No, obviously not, but then the
documentation does warn that a relationship without an inverse is not
recommended* and obeying it seems to fix the problem. I wouldn't call
this a bug, I would expect "the unexpected" to happen in some cases by
going against the recommendations of the documentation for the
technology I'm using.
In your example, you noted that with an inverse relationship, the
problem does not exist and that the documentation clearly states
relationships without an inverse is not recommended. It's safe to
assume this is one of the reasons why. The solution? Add an inverse
relationship as recommended by the documentation ... problem solved.
--
I.S.
* Incidentally, that very premise is the basis for many restraining
orders in the US, so the Courts apparently agree, but I digress ...
On Mar 9, 2007, at 10:31 AM, Aurélien Hugelé wrote:
Hi list!
I just want to stress Core Data users, since i've discovered what I
think is a huge bug, that I reported to apple.
Basically, save an object graph to a SQL store, reload it from disk,
the object graph is not restored correctly, some relationships are
missing.
You can download a very simple project that demonstrate the bug at
http://developer.gumitech.com/CoreDataDramaticalBug.zip
A Readme is included that explains the details.
I'm quite surprised that nobody here has encountered this bug, but
honestly I can't trust Core Data anymore, and I fear a customer
complain about data loss.
Just an optimist note, the bug can't be reproduced on Mac OS X
10.5... But IMHO Apple must fix it on 10.4 too.
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