I'm not sure that's actually a solution. The problem is that if I can specify a
relationship and its inverse in the Core Data model editor, then Core Data
handles setting the opposite end of the relationship for me. Since this is a
generic feature, it can't do what I want, because adding a Segment to a Node
has an ambiguous inverse.
I think the solution is to mark the relationships as not having inverses in the
model, and then manage the inverse relationship myself in code (that is, always
require that a Node be set on a Segment, and that operation will then add the
Segment to the Node).
Can anyone confirm that this is indeed how to solve this problem? Thanks!
On Dec 12, 2009, at 16:43:02, Charlie Dickman wrote:
> Rick,
>
> This can be done in a straightforward manner using C structures that contain
> pointers to the C structures.
>
> For example, you can define structures
>
> typedef node _node {
> segment *someSegment;
> }
>
> typedef struct _segment {
> node node1;
> node node2;
> }
>
> set node.segment to nil in the last segment and chain them together. Remember
> to malloc each instance and free them when they are no longer needed.
>
> This model can easily be transmogrified into Objective C objects.
>
> On Dec 12, 2009, at 7:30 PM, Rick Mann wrote:
>
>> Hi. I'm trying to set up a model for a Node and a Segment. A Segment exists
>> between Nodes. Each Segment has a node1 and node2 attribute, and each Node
>> can have multiple Segments. I don't seem to be able to model this
>> relationship; I can have either node1 with an inverse of segments, or node
>> 2, but not both.
>>
>> It's important for me to distinguish which end of a segment a particular
>> Node is associated with (imagine drawing a directed arrow). I feel like this
>> should be straightforward, but I'm stuck.
>>
>> Any suggestions?
>>
>> TIA,
>> Rick
>>
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>
> Charlie Dickman
> 3tothe...@comcast.net
>
>
>
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