Re: really elementary to-many inverse relationship question
Re: really elementary to-many inverse relationship question
- Subject: Re: really elementary to-many inverse relationship question
- From: "I. Savant" <email@hidden>
- Date: Sat, 2 Dec 2006 20:23:44 -0500
Matt:
When I had this exact problem, I found that at some point I (or,
I'm more convinced, an evil spirit) had unset the inverse
relationship in my MOM. I would have sworn that I'd verified it,
but ... ;-)
Beyond that, all I can say is yes, if your inverse relationship is
properly configured, the inverse should be automatically 'hooked up'.
--
I.S.
On Dec 2, 2006, at 7:19 PM, Matt Neuburg wrote:
I'm initially populating a managed object context "by hand". In my
model, a
Stack entity has to-many relationship "backgrounds" to Background,
and a
Background entity has a to-one relationship "stack" to Stack. Those
relationships are inverses.
In plain English, a stack can have many backgrounds but a
background can
have only one stack.
So I set the background's one stack:
[background setValue: stack forKey: @"stack"];
That works, as I can see through logging. But I also see that the
stack has
no backgrounds.
So the inverse relationship is not being updated automatically. My
question
is: why not? It says right in the docs that it should be:
"Most relationships are inherently bidirectional. Any changes made
to the
relationships between objects should maintain the integrity of the
object
graph. Provided that you have correctly modeled a relationship in both
directions and set the inverses, modifying one end of a relationship
automatically updates the other end."
So is that just not true? I'm perfectly willing to populate both
ends of the
relationship myself, and I am having no difficulty doing so, like
this:
[[stack mutableSetValueForKey:@"backgrounds"] addObject:
background];
I don't mind doing that, but shouldn't I not have to? Thx - m.
--
matt neuburg, phd = email@hidden, http://www.tidbits.com/matt/
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