A generic core data function that can query given entity with the given condition & return sorted results

gistfile1.m

/*
 * A generic function that can query that given entity with the given condition and return sorted results.
 */
-(NSArray *)queryDBForEntity:(NSString *)entityName predicate:(NSPredicate *)predicate sortByField:(NSString *)sortField 
{
    NSFetchRequest *request = [[NSFetchRequest alloc] init]; 
    NSEntityDescription *entity = [NSEntityDescription entityForName:entityName inManagedObjectContext:[self managedObjectContext]]; 
    [request setEntity:entity];
    
    if(sortField != nil)
    {
        NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:sortField ascending:YES]; 
        NSArray *sortDescriptors = [[NSArray alloc]initWithObjects:sortDescriptor, nil]; 
        [request setSortDescriptors:sortDescriptors]; 
        [sortDescriptors release]; 
        [sortDescriptor release];
    }
    
    if(predicate != nil)
        [request setPredicate:predicate];
    
    NSError *error; 
    //    NSMutableArray *mutableFetchResults = [[[self managedObjectContext] executeFetchRequest:request error:&error] mutableCopy]; 
    NSArray *fetchResults = [[self managedObjectContext] executeFetchRequest:request error:&error]; 
    [request release];
    
    if (fetchResults == nil) {
        NSLog(@"Error fetching result %@", [error description]);
    }
    return fetchResults;
}