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Asked: 2026-06-16T00:24:24+00:00

I have three entities: Entity A —– m:n —— Entity B —— m:1 ——

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I have three entities:

Entity A —– m:n —— Entity B —— m:1 —— Entity C

To get the set of B’s belonging to an A, I can use a.b. Since every B has only one C, I’d like to do something to Entity A to be able to say a.c to get the set of C’s. After reading the Apple docs for fetched properties (http://developer.apple.com/library/ios/#documentation/cocoa/conceptual/CoreData/Articles/cdRelationships.html), and thumbing through some fetched property questions here, this doesn’t seem to be the right approach.

Can I use fetched properties to do this? Is there another way?

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1 Answer

  1. Editorial Team

    You can use [a valueForKeyPath:@"b.c"]. This will hand back the value of b.c for every b in a.b.

    More accurately, when an NSArray receives a -valueForKey: call, it constructs a new array containing the results of forwarding that -valueForKey: on to every element in the array. This behavior carries over to -valueForKeyPath: as well. So since the keypath b is an array, the keypath b.c is an array of the key c for every value in the b array.

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