core data - fetch attribute that match one of the values in an array

Question

My core data model:

Person 
======
personId  (NSNumber)

This is a basic core data question,
I have an array of personIds (not Person, just NSNumber of ids) and I want to fetch all the Persons with corresponding id in the array.

This is how I fetch a person that correspond to one id:

   NSFetchRequest *request = [[NSFetchRequest alloc] initWithEntityName:@"Person"];
   request.predicate = [NSPredicate predicateWithFormat:@"personId = %@", onePersonId];

I'm looking for a way to fetch multiple persons that match to multiple ids

score 14 · Accepted Answer · edited Jun 28 '22 at 11:05

14

Use 'IN' match for this:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"personId IN %@", idsArray];

edited Jun 28 '22 at 11:05

Cliff Ribaudo

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answered Mar 06 '14 at 15:06

ksh

1,894
19
20

Its good that Swift can do this much at least. I am used to raw SQL queries which give the real power, but Core Data is very limiting. – zeeshan Jun 01 '16 at 04:27

score 0 · Answer 2 · answered Mar 06 '14 at 15:13

0

Here is code which creates predicate which you are looking for using block.

NSPredicate *predicate= [NSPredicate predicateWithBlock:^BOOL(Person *person, NSDictionary *bind){
    return [arrayOfIds containsObject:person.personId]; //check whether person id is contained within your array of IDs
}];

answered Mar 06 '14 at 15:13

Rafał Augustyniak

2,011
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14

Note that block-based predicates (and Objective-C based predicates in general) cannot be used with a Core Data fetch request. – Martin R Mar 06 '14 at 18:21

score 0 · Answer 3 · answered Jan 06 '18 at 02:27

Swift

let ids: [NSNumber] = [1234, 5678]
let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "YourEntityName")
fetchRequest.predicate = NSPredicate(format: "id IN %@", ids)

Full Example:

func getAllThings(withIds ids: [NSNumber]) -> [Thing] {

    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext

    let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "Thing")
    fetchRequest.predicate = NSPredicate(format: "id IN %@", ids)

    do {
        if let things = try context.fetch(fetchRequest) as? [Thing] {
            return things
        }
    } catch let error as NSError {
        // handle error
    }

    return []
}

core data - fetch attribute that match one of the values in an array

3 Answers3