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POWhy is my NSArray turning into an NSSet?
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10775604
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10775901
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2012-05-27T16:44:14.707
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2012-05-27T17:27:55.580
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2012-05-27T17:20:20.163
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In Objective-C, using core data, I was fetching entities and they were returned as NSArrays. I realized that I was fetching too often and I could make use of the entity's return values, for example: Customer entity has many Invoices, Invoices have many ItemSolds. Here is some code I'm using: <pre><code>NSError *error = nil; // fetch all customers NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Customer" inManagedObjectContext:managedObjectContext]; [fetchRequest setEntity:entity]; self.fetchedCustomers = [managedObjectContext executeFetchRequest:fetchRequest error:&error]; if (fetchedCustomers == nil) { NSLog(@"ERROR"); } [fetchRequest release]; // end of customer fetch </code></pre> This is the simple fetch request, and fetchedCustomers is set as an NSArray property. I then use it's functions : <code>self.fetchedInvoices = [[customerToView valueForKey:@"invoices"] allObjects];</code> This works, and I'm able to display invoice numbers and dates into a table properly. However I then go on to use : <pre><code>self.fetchedObjects = [[fetchedInvoices valueForKey:@"itemsSold"] allObjects]; </code></pre> Later, when I try to add totals I do the following: <pre><code> double price = [[[fetchedObjects objectAtIndex:i] valueForKey:@"Price"] doubleValue]; </code></pre> And I get the following error: <pre><code>-[__NSCFSet doubleValue]: unrecognized selector sent to instance 0x10228f730 </code></pre> Why is there an NSSet involved here at all? When I fetched the invoices and items using predicates, I didn't have any problems, but it seemed really inefficient. I would much rather figure out what's going wrong here. Any help would be appreciated, thanks. Extra info: Areas of interest: <pre><code>@interface Invoice : NSManagedObject { @private } @property (nonatomic, retain) NSSet *itemsSold; @end @interface Invoice (CoreDataGeneratedAccessors) - (void)addItemsSoldObject:(ItemSold *)value; - (void)removeItemsSoldObject:(ItemSold *)value; - (void)addItemsSold:(NSSet *)values; - (void)removeItemsSold:(NSSet *)values; @end </code></pre>
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<objective-c><core-data><nsarray><nsset>
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Why is my NSArray turning into an NSSet?
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