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  1. PO
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    <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:&amp;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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    1. POAdding a float attribute to an entity in coreData and increment it on every addition of new Object
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    1. USMatej Bukovinski
    1. USMatej Bukovinski
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    1. COHi @Matej Whats wrong with my code
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      1. USRanjit
    2. CONot sure. There are a lot of unknowns here, while the code I posted should work in any case, as long as you save the MOC after each insertion, which you do. Are you reloading self.controller before every insert call? Are you sorting the objects by displayOrder (appropriate sort descriptor for the fetch request)? NSLog self.controller.fetchedObjects and see how your objects look like. You are also mixing NSNumber double and float methods, although that's likely not the issue here. You should really be using integers for this property, I suggest you change the model.
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      1. USMatej Bukovinski
    3. COYes, I am sorting the objects by displayOrder.how to use your function , is this the right way to pass the value to the attribute [test setdisplayOrder:[self nextDisplayOrder];
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