fetching particular predicate from database

I have 4 CoreData database. Each actually having their own value. But it is too heavy and i would like to reduce it to 1 Database. So each time i want to pull information from the database, i can choose what to pull. I need to use NSPredicate to set the string that i want to pull izzit?

Do i set my NSPredicate like this?

NSString *value = @"Food";
NSString *wildcardedString = [NSString stringWithFormat:@"%@*", value];
[[NSPredicate predicateWithFormat:@"ANY places.type like %@", wildcardedString];

and how do i bind the NSPredicate with the fetch request sequence?

this is my fetchedResultsController

- (NSFetchedResultsController *)fetchedResultsController {
    if (fetchedResultsController != nil) 
    {
        return fetchedResultsController;
    }

    CoreDataMelakaAppDelegate *appDelegate = (CoreDataMelakaAppDelegate *)[[UIApplication sharedApplication] delegate];
    NSManagedObjectContext *context = [appDelegate managedObjectContext];
    NSFetchRequest *fetchRequest = [[[NSFetchRequest alloc] init] autorelease];
    [fetchRequest setEntity:[NSEntityDescription entityForName:@"WhereTo" inManagedObjectContext:context]];
    NSSortDescriptor *sortDescriptor = [[[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES] autorelease];
    NSArray *sortDescriptors = [[[NSArray alloc] initWithObjects:sortDescriptor, nil] autorelease];
    [fetchRequest setSortDescriptors:sortDescriptors];
   // NSPredicate *pred = [NSPredicate predicateWithFormat:@"(name = %@)", wher.name];
    //[fetchRequest setPredicate:pred];
    NSString *value = @"Nasi";
    NSString *wildcardedString = [NSString stringWithFormat:@"%@*", value];
    [[NSPredicate predicateWithFormat:@"ANY wher.name like %@", wildcardedString];
    NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectConte开发者_如何学Pythonxt:context sectionNameKeyPath:nil cacheName:@"Root"];
    aFetchedResultsController.delegate = self;
    self.fetchedResultsController = aFetchedResultsController;
    [aFetchedResultsController release];
    return fetchedResultsController;
}  

When you alter the predicate of a fetch request used by a fetched results controller (FRC), you have to create a new fetched results controller.

Your code is fine logically but it only creates a FRC once with a predicate that compiles to:

ANY wher.name like Nasi*

... each time the FRC executes its fetch, it use that exact predicate.

If you want to use a flexible predicate, you will need to create a new FRC every time you change the predicate.