Re: Core Data: Need help with fetch request
Re: Core Data: Need help with fetch request
- Subject: Re: Core Data: Need help with fetch request
- From: Diederik Hoogenboom <email@hidden>
- Date: Sun, 15 Oct 2006 14:02:12 +0200
Jakob,
When I designed the model I though I would never have to go the other
way (in the example from Wheels to Cars). I can add the relationship
and then it would probably work. Unfortunately, I now have to
convert the whole persistent store from the old model to the new
model just for one relationship! If I add the relationship the old
store will complain that the field is unkown (eventough it's set to
'optional'. Oh well, that's what you get from not following the
rules ;-).
Diederik
On 14-okt-2006, at 17:17, Jakob Olesen wrote:
On 10/10/2006, at 21.27, Diederik Hoogenboom wrote:
I want to fetch some objects based on a condition existing in one
of its relationships.
Example Object Model:
Car -> Wheel
A car can have one or more wheels. And a wheel has a property
called color (to keep it simple an NSString). The relationship is
called wheels. There is no inverse relationship.
What is your really, really good reason for not having an inverse
relationship?
Is it one-to-many or many-to-many?
Unfortunately the fetch request does result in any objects retrieved.
I am using an SQL-lite store for this example.
What does the generated SQL look like?
Does it change if you add an inverse relationship?
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