How to select specific data in Core Data? - iphone

Question

I have a sample program that use Core Data and load an sqlite database in it. And I am displaying all the values using this code
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Name"
inManagedObjectContext:context];
[fetchRequest setEntity:entity];
NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
for (Name *name in fetchedObjects) {
NSLog(#"ID: %#", name.nameId);
NSLog(#"First Name: %#", name.first);
NSLog(#"Middle Name: %#", name.middle);
NSLog(#"Last Name: %#", name.last);
}
This code works fine, my problem here is that I can't select a specific data/record. Example I want to select the record with the ID = 1.
Thanks!

Answer 1

You have to use predicates (with NSPredicate) before your request execution.
Something like that :
NSPredicate *predicateID = [NSPredicate predicateWithFormat:#"nameID == %d",-1];
[fetchRequest setPredicate:predicateID];

Answer 2

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:#"Name"
inManagedObjectContext:context];
[fetchRequest setEntity:entity];
//Add following method to your code. this will help you to get desired result.
[fetchRequest setPredicate:[NSPredicate predicateWithFormat:#"yourColumnID == %#", yourID]];
NSArray *fetchedObjects = [context executeFetchRequest:fetchRequest error:&error];
for (Name *name in fetchedObjects) {
NSLog(#"ID: %#", name.nameId);
NSLog(#"First Name: %#", name.first);
NSLog(#"Middle Name: %#", name.middle);
NSLog(#"Last Name: %#", name.last);
}