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POSorting an NSFetchRequest Based on a Property within a One-to-Many Relationship?
 

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  1. POSorting an NSFetchRequest Based on a Property within a One-to-Many Relationship?
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    <p>I've been prowling through the SO search results and can't (thus far) find an answer to this question.</p> <p>Given a data entity A that has a one-to-many relationship to entity B, is there any way to have my NSFetchedResult sort on a <em>property</em> of entity B. i.e. Can I have my sort descriptor key drill down into entity B? I've tried dot notation, etc, but nothing is working.</p> <p>e.g. Entity A has a relationship <code>inEntityB</code>. Entity B has a property <code>entityBproperty</code>. How can I sort a list of Entity A's based on the <code>entityBproperty</code> value of their respective <code>inEntityB</code> relationships?</p> <p>Something like (and no this doesn't work):</p> <pre><code>request.sortDescriptors = [NSArray arrayWithObjects: [NSSortDescriptor sortDescriptorWithKey:@"entityAproperty" ascending:NO selector:@selector(localizedStandardCompare:)], [NSSortDescriptor sortDescriptorWithKey:@"inEntityB.entityBproperty" ascending:NO selector:@selector(localizedStandardCompare:)], nil]; </code></pre> <p>It seems awfully inefficient to duplicate, in Entity A, the <code>entityBproperty</code> that I want to sort by. Isn't the whole point of relationships that you can compartmentalize your data model to keep it more manageable?</p> <p>Any advice much appreciated! Thanks!</p> <p><strong>Edit:</strong> I'm not really sure what additional information I can add to help clarify the question, but given the lack of response thus far, if anyone has suggestions for what else I might add here, I'm all ears. Unfortunately I don't have bounty privileges yet, or I'd consider one in this case, as this seems like a potentially more obscure question.</p>
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    1. USJ Sreedhar
    1. USMurdock
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      1. POSorting an NSFetchRequest Based on a Property within a One-to-Many Relationship?
      1. USAmit Singh
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    1. COdid you find a solution or a work-around to this problem? I have exactly the same situation. Please let me know if you can provide anything helpful. Thank you.
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      1. USKDaker
    2. COUnfortunately not. It seems like there must be a way to do it, though. You may be able to do it using dynamic attributes.
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      1. POSorting an NSFetchRequest Based on a Property within a One-to-Many Relationship?
      1. USMurdock
    3. COAre we asking the same question? Here's mine: http://stackoverflow.com/questions/13002915/possible-for-an-nssortdescriptor-to-use-a-specific-object-in-a-to-many-relations
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      1. POSorting an NSFetchRequest Based on a Property within a One-to-Many Relationship?
      1. USBryan Irace
 

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