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copied!<p>You could use Core Data Aggregate Functions to get the maximum displayOrder value. </p> <p>Something like: </p> <pre><code>- (NSNumber *)nextDisplayOrder { NSManagedObjectContext *context = self.managedObjectContext; NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Test" inManagedObjectContext:context]; NSFetchRequest *request = [[NSFetchRequest alloc] init]; [request setEntity:entityDescription]; [request setResultType:NSDictionaryResultType]; NSExpression *keyExpression = [NSExpression expressionForKeyPath:@"displayOrder"]; NSExpression *maxExpression = [NSExpression expressionForFunction:@"max:" arguments:[NSArray arrayWithObject:keyExpression]]; NSExpressionDescription *description = [[NSExpressionDescription alloc] init]; [description setName:@"maxDisplayOrder"]; [description setExpression:maxExpression]; [description setExpressionResultType:NSFloatAttributeType]; [request setPropertiesToFetch:[NSArray arrayWithObject:description]]; NSError *error = nil; NSArray *results = [context executeFetchRequest:request error:&error]; if (results.count == 1) { NSNumber *maxDisplayOrder = [[results objectAtIndex:0] valueForKey:@"displayOrder"]; return [NSNumber numberWithFloat:[maxDisplayOrder floatValue] + 1.f]; } else { NSLog(@"Could not get next displayOrder. Error: %@", error); } return nil; } </code></pre> <p>Some additional notes:</p> <ul> <li>use an integer rather than a float for discrete values like the displayOrder</li> <li>this boilerplate code can be written in 2 lines with <a href="https://github.com/magicalpanda/MagicalRecord" rel="nofollow">MagicalRecord</a>, so you might want to check that out</li> <li><a href="http://brianflove.com/2012/09/26/core-data-aggregate-functions/" rel="nofollow">more info on aggregate functions</a></li> </ul>

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