Select specific attribute in entity Core Data

I'm searching how to select all values for a specific attribute in an entity in Core Data.

Here my model:

I have an entity named "Countries" with 3 attributes of type "String":

• name_en
• name_fr
• name_de

I display the values on a UITableView, but I would like only show the values from name_en OR name_fr OR name_de based on the user default language. At the moment, all the values are selected (name_en, name_fr and name_de).

The solution (Thanks to Simon):

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%K MATCHES %@", [NSString stringWithFormat:@"name_%@",[Config getCurrentLocale]], @".{1,}"];

Where [Config getCurrentLocale] returns me "fr" OR "de" OR "en".

Next, apply this predicate to the request:

NSFetchRequest * request = [self defaultRequest];

request.predicate = predicate;

self.fetchedResultsController = 
[[NSFetchedResultsController alloc] initWithFetchRequest:request
                                    managedObjectContext:context
                                      sectionNameKeyPath:nil
                                               cacheName:nil];

========= Relative to my problem (Resolved now) ==========

Here is my method where I build the fetch request:

-(NSFetchRequest *) defaultRequest
{

    NSFetchRequest * request = [[NSFetchRequest alloc] init];
    NSEntityDescription * entity = [NSEntityDescription entityForName:self.entityName
                                            inManagedObjectContext:appDelegate.managedObjectContext];
    NSDictionary *attributes = [entity attributesByName];

    // Put some stuff here to "filter" the request and show only name_en OR name_fr OR name_de ?
    request.entity = entity;
    request.fetchBatchSize = 20;
    //request.fetchLimit = 50;

    request.sortDescriptors = self.defaultSortDescriptors;

    return request;

}

Thank you guys for your help.

EDIT 1

Here is the data source methods of my subclass of UITableViewController:

#pragma mark - UITableView

- (NSFetchedResultsController *)fetchedResultsControllerForTableView:(UITableView *)tableView
{
    if (tableView == self.searchDisplayController.searchResultsTableView)
        return self.searchFetchedResultsController;

    if (tableView == self.tableView)
        return self.fetchedResultsController;

    return nil;
}

#pragma mark DataSource

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return [[[self fetchedResultsControllerForTableView:tableView] sections] count];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [[[[self fetchedResultsControllerForTableView:tableView] sections] objectAtIndex:section] numberOfObjects];
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section
{
    return [[[[self fetchedResultsControllerForTableView:tableView] sections] objectAtIndex:section] name];
}

- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index
{
    return [[self fetchedResultsControllerForTableView:tableView] sectionForSectionIndexTitle:title atIndex:index];
}

- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView
{
    return [[self fetchedResultsControllerForTableView:tableView] sectionIndexTitles];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSString * identifier = [self cellIdentifierForIndexPath:indexPath];
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identifier];

    if (cell == nil)
        cell = [self newTableViewCellWithIndentifier:identifier];

    // Configure the cell.
    [self tableView:tableView configureCell:cell atIndexPath:indexPath];

    return cell;
}

EDIT 2:

I try something like this just to show the results in outputs:

 NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Countries"];

    fetchRequest.resultType = NSDictionaryResultType;

    [fetchRequest setPropertiesToFetch:[NSArray arrayWithObjects:@"name_en", nil]];

    NSError *error      = nil;
    NSArray *results    = [[AppDelegate sharedInstance].managedObjectContext executeFetchRequest:fetchRequest error:&error];

    NSMutableArray *countries = [results valueForKey:@"name_en"];

    NSLog(@"Count: %d", countries.count);

Normally, I have around 246 countries in name_en, and the count is 757! So, the sum of name_fr + name_en + name_de... I don't understand why :(

Edit => I found a solution here: How to fetch unique field values (song_type) from core data

Now, I have to adapt my code to works with this piece of code :)